<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.ielp.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesDetails" xlink:href="iep-20180331.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesNotes" xlink:href="iep-20180331.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesNotes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:href="iep-20180331.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesTables" xlink:href="iep-20180331.xsd#BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/ChangesInAccumulatedOtherComprehensiveLoss" xlink:href="iep-20180331.xsd#ChangesInAccumulatedOtherComprehensiveLoss" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/ChangesInAccumulatedOtherComprehensiveLossDetails" xlink:href="iep-20180331.xsd#ChangesInAccumulatedOtherComprehensiveLossDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/ChangesInAccumulatedOtherComprehensiveLossTables" xlink:href="iep-20180331.xsd#ChangesInAccumulatedOtherComprehensiveLossTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CommitmentsAndContingencies" xlink:href="iep-20180331.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CommitmentsAndContingenciesDetails" xlink:href="iep-20180331.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CondensedBalanceSheetsByReportingSegmentDetails" xlink:href="iep-20180331.xsd#CondensedBalanceSheetsByReportingSegmentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CondensedConsolidatedBalanceSheets" xlink:href="iep-20180331.xsd#CondensedConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CondensedConsolidatedBalanceSheetsParentheticals" xlink:href="iep-20180331.xsd#CondensedConsolidatedBalanceSheetsParentheticals" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CondensedConsolidatedStatementsOfCashFlows" xlink:href="iep-20180331.xsd#CondensedConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CondensedConsolidatedStatementsOfChangesInEquity" xlink:href="iep-20180331.xsd#CondensedConsolidatedStatementsOfChangesInEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CondensedConsolidatedStatementsOfComprehensiveIncome" xlink:href="iep-20180331.xsd#CondensedConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CondensedConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:href="iep-20180331.xsd#CondensedConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CondensedConsolidatedStatementsOfOperations" xlink:href="iep-20180331.xsd#CondensedConsolidatedStatementsOfOperations" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/CondensedStatementOfOperationsByReportingSegmentDetails" xlink:href="iep-20180331.xsd#CondensedStatementOfOperationsByReportingSegmentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/Debt" xlink:href="iep-20180331.xsd#Debt" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/DebtDetails" xlink:href="iep-20180331.xsd#DebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/DebtTables" xlink:href="iep-20180331.xsd#DebtTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/DescriptionOfBusiness" xlink:href="iep-20180331.xsd#DescriptionOfBusiness" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/Details" xlink:href="iep-20180331.xsd#Details" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/DocumentAndEntityInformationDocument" xlink:href="iep-20180331.xsd#DocumentAndEntityInformationDocument" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FairValueMeasurements" xlink:href="iep-20180331.xsd#FairValueMeasurements" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FairValueMeasurementsChangesInFairValueLevel3Details" xlink:href="iep-20180331.xsd#FairValueMeasurementsChangesInFairValueLevel3Details" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FairValueMeasurementsFairValueMeasurementDetails" xlink:href="iep-20180331.xsd#FairValueMeasurementsFairValueMeasurementDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FairValueMeasurementsNarrativeDetails" xlink:href="iep-20180331.xsd#FairValueMeasurementsNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FairValueMeasurementsPolicies" xlink:href="iep-20180331.xsd#FairValueMeasurementsPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FairValueMeasurementsTables" xlink:href="iep-20180331.xsd#FairValueMeasurementsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FinancialInstruments" xlink:href="iep-20180331.xsd#FinancialInstruments" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FinancialInstrumentsDerivativeActivitiesTableDetails" xlink:href="iep-20180331.xsd#FinancialInstrumentsDerivativeActivitiesTableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FinancialInstrumentsDerivativesNotDesignatedAsHedgingFairValueTableDetails" xlink:href="iep-20180331.xsd#FinancialInstrumentsDerivativesNotDesignatedAsHedgingFairValueTableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FinancialInstrumentsGainLossRecognizedOnDerivativesNotDesignatedAsHedgingTableDetails" xlink:href="iep-20180331.xsd#FinancialInstrumentsGainLossRecognizedOnDerivativesNotDesignatedAsHedgingTableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FinancialInstrumentsNarrativeDetails" xlink:href="iep-20180331.xsd#FinancialInstrumentsNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FinancialInstrumentsNonDerivativeFinancialInstrumentsDesignatedAsHedgingDetails" xlink:href="iep-20180331.xsd#FinancialInstrumentsNonDerivativeFinancialInstrumentsDesignatedAsHedgingDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/FinancialInstrumentsTables" xlink:href="iep-20180331.xsd#FinancialInstrumentsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNet" xlink:href="iep-20180331.xsd#GoodwillAndIntangibleAssetsNet" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNetDefiniteLivedAndIndefiniteLivedIntangibleAssetsTableDetails" xlink:href="iep-20180331.xsd#GoodwillAndIntangibleAssetsNetDefiniteLivedAndIndefiniteLivedIntangibleAssetsTableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNetGoodwillTableDetails" xlink:href="iep-20180331.xsd#GoodwillAndIntangibleAssetsNetGoodwillTableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNetNarrativeDetails" xlink:href="iep-20180331.xsd#GoodwillAndIntangibleAssetsNetNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNetTables" xlink:href="iep-20180331.xsd#GoodwillAndIntangibleAssetsNetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/IncomeTaxes" xlink:href="iep-20180331.xsd#IncomeTaxes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/IncomeTaxesIncomeTaxesDetails" xlink:href="iep-20180331.xsd#IncomeTaxesIncomeTaxesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/InventoriesNetDetails" xlink:href="iep-20180331.xsd#InventoriesNetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/InventoriesNetNotes" xlink:href="iep-20180331.xsd#InventoriesNetNotes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/InventoriesNetTables" xlink:href="iep-20180331.xsd#InventoriesNetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/InvestmentsAndRelatedMatters" xlink:href="iep-20180331.xsd#InvestmentsAndRelatedMatters" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/InvestmentsAndRelatedMattersInvestmentSegmentDetails" xlink:href="iep-20180331.xsd#InvestmentsAndRelatedMattersInvestmentSegmentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/InvestmentsAndRelatedMattersOtherSegmentsDetails" xlink:href="iep-20180331.xsd#InvestmentsAndRelatedMattersOtherSegmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/InvestmentsAndRelatedMattersTables" xlink:href="iep-20180331.xsd#InvestmentsAndRelatedMattersTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/NetIncomePerLpUnit" xlink:href="iep-20180331.xsd#NetIncomePerLpUnit" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/NetIncomePerLpUnitDetails" xlink:href="iep-20180331.xsd#NetIncomePerLpUnitDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/NetIncomePerLpUnitTables" xlink:href="iep-20180331.xsd#NetIncomePerLpUnitTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/OtherIncomeLossNet" xlink:href="iep-20180331.xsd#OtherIncomeLossNet" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/OtherIncomeLossNetDetails" xlink:href="iep-20180331.xsd#OtherIncomeLossNetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/OtherIncomeLossNetTables" xlink:href="iep-20180331.xsd#OtherIncomeLossNetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/PensionsOtherPostRetirementBenefitsAndEmployeeBenefitPlans" xlink:href="iep-20180331.xsd#PensionsOtherPostRetirementBenefitsAndEmployeeBenefitPlans" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/PensionsOtherPostRetirementBenefitsAndEmployeeBenefitPlansDetails" xlink:href="iep-20180331.xsd#PensionsOtherPostRetirementBenefitsAndEmployeeBenefitPlansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/PensionsOtherPostRetirementBenefitsAndEmployeeBenefitPlansTables" xlink:href="iep-20180331.xsd#PensionsOtherPostRetirementBenefitsAndEmployeeBenefitPlansTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/RelatedPartyTransactions" xlink:href="iep-20180331.xsd#RelatedPartyTransactions" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/RelatedPartyTransactionsDetails" xlink:href="iep-20180331.xsd#RelatedPartyTransactionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/SegmentReporting" xlink:href="iep-20180331.xsd#SegmentReporting" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/SegmentReportingDisaggregationOfRevenueDetails" xlink:href="iep-20180331.xsd#SegmentReportingDisaggregationOfRevenueDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/SegmentReportingPolicies" xlink:href="iep-20180331.xsd#SegmentReportingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/SegmentReportingTables" xlink:href="iep-20180331.xsd#SegmentReportingTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/SubsequentEvents" xlink:href="iep-20180331.xsd#SubsequentEvents" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/SubsequentEventsDetails" xlink:href="iep-20180331.xsd#SubsequentEventsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/SupplementalCashFlowInformationDetails" xlink:href="iep-20180331.xsd#SupplementalCashFlowInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/SupplementalCashFlowInformationNotes" xlink:href="iep-20180331.xsd#SupplementalCashFlowInformationNotes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.ielp.com/role/SupplementalCashFlowInformationTables" xlink:href="iep-20180331.xsd#SupplementalCashFlowInformationTables" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesDetails" xlink:type="extended">
    <link:loc xlink:href="iep-20180331.xsd#iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems" xlink:label="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:type="locator" />
    <link:loc xlink:href="iep-20180331.xsd#iep_OrganizationConsolidationandPresentationofFinancialStatementsTable" xlink:label="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredRevenueArrangementTypeAxis" xlink:label="loc_us-gaap_DeferredRevenueArrangementTypeAxis_D3BAFFE985DA8DF373AC216C4272EAFA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:to="loc_us-gaap_DeferredRevenueArrangementTypeAxis_D3BAFFE985DA8DF373AC216C4272EAFA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredRevenueArrangementTypeDomain" xlink:label="loc_us-gaap_DeferredRevenueArrangementTypeDomain_BFA1F86C61AED6BD4F3421A7603520CF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DeferredRevenueArrangementTypeAxis_D3BAFFE985DA8DF373AC216C4272EAFA" xlink:to="loc_us-gaap_DeferredRevenueArrangementTypeDomain_BFA1F86C61AED6BD4F3421A7603520CF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredRevenueArrangementTypeDomain" xlink:label="loc_us-gaap_DeferredRevenueArrangementTypeDomain_BFA1F86C61AED6BD4F3421A7603520CF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DeferredRevenueArrangementTypeAxis_D3BAFFE985DA8DF373AC216C4272EAFA" xlink:to="loc_us-gaap_DeferredRevenueArrangementTypeDomain_BFA1F86C61AED6BD4F3421A7603520CF" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ProductreturnsMember" xlink:label="loc_iep_ProductreturnsMember_797468F878B28B34E061216CCB09CCDE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredRevenueArrangementTypeDomain_BFA1F86C61AED6BD4F3421A7603520CF" xlink:to="loc_iep_ProductreturnsMember_797468F878B28B34E061216CCB09CCDE" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ExtendedwarrantiesMember" xlink:label="loc_iep_ExtendedwarrantiesMember_1A12B6B5238C18325B23216D7DFBD89C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredRevenueArrangementTypeDomain_BFA1F86C61AED6BD4F3421A7603520CF" xlink:to="loc_iep_ExtendedwarrantiesMember_1A12B6B5238C18325B23216D7DFBD89C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_FD3CE03EF5C7495EA498216009762C4C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_FD3CE03EF5C7495EA498216009762C4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_855ABE4DCD45E9B950F121A80C36AB8D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_FD3CE03EF5C7495EA498216009762C4C" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_855ABE4DCD45E9B950F121A80C36AB8D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_855ABE4DCD45E9B950F121A80C36AB8D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_FD3CE03EF5C7495EA498216009762C4C" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_855ABE4DCD45E9B950F121A80C36AB8D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member" xlink:label="loc_us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_02CF6C8267F8BF70494A21603B9300EC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_855ABE4DCD45E9B950F121A80C36AB8D" xlink:to="loc_us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_02CF6C8267F8BF70494A21603B9300EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_A7031B3A23147F1F830D215A986BEB4E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_A7031B3A23147F1F830D215A986BEB4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_5A4C1C4399DA917D2ABB215A986BE6C7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_A7031B3A23147F1F830D215A986BEB4E" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_5A4C1C4399DA917D2ABB215A986BE6C7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_5A4C1C4399DA917D2ABB215A986BE6C7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_A7031B3A23147F1F830D215A986BEB4E" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_5A4C1C4399DA917D2ABB215A986BE6C7" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_StatementofcashflowlocationAxis" xlink:label="loc_iep_StatementofcashflowlocationAxis_B039C99B26CDED4B5618215A986B673B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:to="loc_iep_StatementofcashflowlocationAxis_B039C99B26CDED4B5618215A986B673B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_StatementofcashflowlocationDomain" xlink:label="loc_iep_StatementofcashflowlocationDomain_C543698EBB5525B8278C215A986B882D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_iep_StatementofcashflowlocationAxis_B039C99B26CDED4B5618215A986B673B" xlink:to="loc_iep_StatementofcashflowlocationDomain_C543698EBB5525B8278C215A986B882D_default" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_StatementofcashflowlocationDomain" xlink:label="loc_iep_StatementofcashflowlocationDomain_C543698EBB5525B8278C215A986B882D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_iep_StatementofcashflowlocationAxis_B039C99B26CDED4B5618215A986B673B" xlink:to="loc_iep_StatementofcashflowlocationDomain_C543698EBB5525B8278C215A986B882D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_NetcashprovidedbyoperatingactivitiesMember" xlink:label="loc_iep_NetcashprovidedbyoperatingactivitiesMember_86A6F0E4B30D8FC96477215A986BEBEB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_StatementofcashflowlocationDomain_C543698EBB5525B8278C215A986B882D" xlink:to="loc_iep_NetcashprovidedbyoperatingactivitiesMember_86A6F0E4B30D8FC96477215A986BEBEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_C11696E924DDF5E7608A215A986CA673" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_C11696E924DDF5E7608A215A986CA673" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_7BB9CA9C432180F41194215A986DBBB2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_C11696E924DDF5E7608A215A986CA673" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_7BB9CA9C432180F41194215A986DBBB2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_7BB9CA9C432180F41194215A986DBBB2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_C11696E924DDF5E7608A215A986CA673" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_7BB9CA9C432180F41194215A986DBBB2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_C42803B7CC70886B4758215A986DAF63" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_7BB9CA9C432180F41194215A986DBBB2" xlink:to="loc_us-gaap_CostOfSalesMember_C42803B7CC70886B4758215A986DAF63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_2A3E0B9BF2357E3ED5CD215A986D0F48" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_7BB9CA9C432180F41194215A986DBBB2" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_2A3E0B9BF2357E3ED5CD215A986D0F48" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherIncomeMember" xlink:label="loc_us-gaap_OtherIncomeMember_D88FAB7C4B0699B79650215A986D99B4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_7BB9CA9C432180F41194215A986DBBB2" xlink:to="loc_us-gaap_OtherIncomeMember_D88FAB7C4B0699B79650215A986D99B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_A912455C870128AB58F1215A986D1304" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_A912455C870128AB58F1215A986D1304" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_A912455C870128AB58F1215A986D1304" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_A912455C870128AB58F1215A986D1304" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsMember" xlink:label="loc_us-gaap_CashAndCashEquivalentsMember_7BF7DE42728103842CD0215A986EF538" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_us-gaap_CashAndCashEquivalentsMember_7BF7DE42728103842CD0215A986EF538" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_CashheldatconsolidatedaffiliatedpartnershipsandrestrictedcashMember" xlink:label="loc_iep_CashheldatconsolidatedaffiliatedpartnershipsandrestrictedcashMember_D8887B4F8755A2E67CD6215A98715F2F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_iep_CashheldatconsolidatedaffiliatedpartnershipsandrestrictedcashMember_D8887B4F8755A2E67CD6215A98715F2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentsMember" xlink:label="loc_us-gaap_InvestmentsMember_C5AFB217D178B06B832C215A9871F924" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_us-gaap_InvestmentsMember_C5AFB217D178B06B832C215A9871F924" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_DueFromBrokerMember" xlink:label="loc_iep_DueFromBrokerMember_0F4A2804DD3D687F5A22215A98712D50" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_iep_DueFromBrokerMember_0F4A2804DD3D687F5A22215A98712D50" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentMember" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentMember_9D873EDB841FDA1C9267215A987266B8" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentMember_9D873EDB841FDA1C9267215A987266B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoriesMember" xlink:label="loc_us-gaap_InventoriesMember_BEF00A10870365E41674215A9872A32C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_us-gaap_InventoriesMember_BEF00A10870365E41674215A9872A32C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IntangibleassetsnetMember" xlink:label="loc_iep_IntangibleassetsnetMember_0A0F33C35C62BABD0CF1215A98729602" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_iep_IntangibleassetsnetMember_0A0F33C35C62BABD0CF1215A98729602" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsMember" xlink:label="loc_us-gaap_OtherAssetsMember_33BF078F335A5A412F53215A9872A640" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_us-gaap_OtherAssetsMember_33BF078F335A5A412F53215A9872A640" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AccountspayableaccruedexpensesandotherliabilitiesMember" xlink:label="loc_iep_AccountspayableaccruedexpensesandotherliabilitiesMember_6D69FFE4D147711404D6215A98725433" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_iep_AccountspayableaccruedexpensesandotherliabilitiesMember_6D69FFE4D147711404D6215A98725433" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SecuritiesSoldNotYetPurchasedMember" xlink:label="loc_us-gaap_SecuritiesSoldNotYetPurchasedMember_6E792FD3A5E6ECC68359215A98729520" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_us-gaap_SecuritiesSoldNotYetPurchasedMember_6E792FD3A5E6ECC68359215A98729520" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_DuetobrokersMember" xlink:label="loc_iep_DuetobrokersMember_9032E6BF65744933078D215A9872A8B9" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_iep_DuetobrokersMember_9032E6BF65744933078D215A9872A8B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtMember" xlink:label="loc_us-gaap_DebtMember_A2DC8B227137464FBC9C215A98737E47" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_AD6125544F06315FB2C8215A986D98AD" xlink:to="loc_us-gaap_DebtMember_A2DC8B227137464FBC9C215A98737E47" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_5204D3EE3ED8602C0DB2215A9873000D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:to="loc_dei_LegalEntityAxis_5204D3EE3ED8602C0DB2215A9873000D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_61A6636E2C6ECB888A45215A9873DFD1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_5204D3EE3ED8602C0DB2215A9873000D" xlink:to="loc_dei_EntityDomain_61A6636E2C6ECB888A45215A9873DFD1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_61A6636E2C6ECB888A45215A9873DFD1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_5204D3EE3ED8602C0DB2215A9873000D" xlink:to="loc_dei_EntityDomain_61A6636E2C6ECB888A45215A9873DFD1" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_1E25AB541B3DF30BE926215A9873400F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_61A6636E2C6ECB888A45215A9873DFD1" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_1E25AB541B3DF30BE926215A9873400F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_E2A7A4A86D1FDE2F8A47215A9873CBF1" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_E2A7A4A86D1FDE2F8A47215A9873CBF1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_6839512DD46986A9A5D5215A9873440E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_E2A7A4A86D1FDE2F8A47215A9873CBF1" xlink:to="loc_us-gaap_SegmentDomain_6839512DD46986A9A5D5215A9873440E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_6839512DD46986A9A5D5215A9873440E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_E2A7A4A86D1FDE2F8A47215A9873CBF1" xlink:to="loc_us-gaap_SegmentDomain_6839512DD46986A9A5D5215A9873440E" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_2B0DC553F1CB28F3F89D215A987329F4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6839512DD46986A9A5D5215A9873440E" xlink:to="loc_iep_AutomotiveSegmentMember_2B0DC553F1CB28F3F89D215A987329F4" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_3A8BDBF5B55961C01AF4215A98743E43" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6839512DD46986A9A5D5215A9873440E" xlink:to="loc_iep_EnergySegmentMember_3A8BDBF5B55961C01AF4215A98743E43" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RailcarSegmentMember" xlink:label="loc_iep_RailcarSegmentMember_CB04FFA0F2CFF30D3A7F215A9874DE75" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6839512DD46986A9A5D5215A9873440E" xlink:to="loc_iep_RailcarSegmentMember_CB04FFA0F2CFF30D3A7F215A9874DE75" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_CC9AE08D82544E01FDC6215A987489A8" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_3D2C7260FE37722C6B13215A986AC07B" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_CC9AE08D82544E01FDC6215A987489A8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_CFB9CDD045997229EE19215A9874BC6F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_CC9AE08D82544E01FDC6215A987489A8" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_CFB9CDD045997229EE19215A9874BC6F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_CFB9CDD045997229EE19215A9874BC6F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_CC9AE08D82544E01FDC6215A987489A8" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_CFB9CDD045997229EE19215A9874BC6F" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RestrictedCashMember" xlink:label="loc_iep_RestrictedCashMember_5924D616BFD06BB62A3A215A9874F891" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_CFB9CDD045997229EE19215A9874BC6F" xlink:to="loc_iep_RestrictedCashMember_5924D616BFD06BB62A3A215A9874F891" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PriorPeriodReclassificationAdjustment" xlink:label="loc_us-gaap_PriorPeriodReclassificationAdjustment_D8EDB11D09DD235481D2215A98748D58" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_PriorPeriodReclassificationAdjustment_D8EDB11D09DD235481D2215A98748D58" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1" xlink:label="loc_us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1_CD1414B7CE9896EA4F11215A98745486" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1_CD1414B7CE9896EA4F11215A98745486" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_665D6320E74F5C6D2F94216F321EFAF8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_InventoryNet_665D6320E74F5C6D2F94216F321EFAF8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest" xlink:label="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_EE34B47208051A7C15B0215A987596D4" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_EE34B47208051A7C15B0215A987596D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntityConsolidatedCarryingAmountAssets" xlink:label="loc_us-gaap_VariableInterestEntityConsolidatedCarryingAmountAssets_0B509999350278D61C9F215A98753E4C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_VariableInterestEntityConsolidatedCarryingAmountAssets_0B509999350278D61C9F215A98753E4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities" xlink:label="loc_us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities_EAB5FACEDB60708D0256215A9875E607" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities_EAB5FACEDB60708D0256215A9875E607" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtAndCapitalLeaseObligations" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_6BAD83BD77E9951888EE215A98758F34" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_6BAD83BD77E9951888EE215A98758F34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtFairValue" xlink:label="loc_us-gaap_LongTermDebtFairValue_293C824C07834D23B2C5215A98756A4E" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_LongTermDebtFairValue_293C824C07834D23B2C5215A98756A4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalents" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents_4AB67A0871B87F86243B215A98753EBF" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalents_4AB67A0871B87F86243B215A98753EBF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestsContinuedToBeHeldByTransferorFairValue" xlink:label="loc_us-gaap_InterestsContinuedToBeHeldByTransferorFairValue_36B1EF3DADAADB00CDC9215A9875AE4D" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_InterestsContinuedToBeHeldByTransferorFairValue_36B1EF3DADAADB00CDC9215A9875AE4D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_GrossAccountsReceivableFactoredQualifyingAsSales" xlink:label="loc_iep_GrossAccountsReceivableFactoredQualifyingAsSales_125E75B225D0C411998C215A9875906D" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_iep_GrossAccountsReceivableFactoredQualifyingAsSales_125E75B225D0C411998C215A9875906D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashFlowsBetweenTransfereeAndTransferorProceedsFromNewTransfers" xlink:label="loc_us-gaap_CashFlowsBetweenTransfereeAndTransferorProceedsFromNewTransfers_92676DCFC1A2BDCB3C05215A987522E2" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_CashFlowsBetweenTransfereeAndTransferorProceedsFromNewTransfers_92676DCFC1A2BDCB3C05215A987522E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleGainLossOnSale" xlink:label="loc_us-gaap_SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleGainLossOnSale_9A5AEC9A9B051A06958D215A987670BE" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleGainLossOnSale_9A5AEC9A9B051A06958D215A987670BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredRevenue" xlink:label="loc_us-gaap_DeferredRevenue_7220788DCDCEF3CC555F215A9876A4AD" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_DeferredRevenue_7220788DCDCEF3CC555F215A9876A4AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredRevenueRevenueRecognized1" xlink:label="loc_us-gaap_DeferredRevenueRevenueRecognized1_1C287CAA788640610A31215A9876BF30" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_DeferredRevenueRevenueRecognized1_1C287CAA788640610A31215A9876BF30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredRevenueNoncurrent" xlink:label="loc_us-gaap_DeferredRevenueNoncurrent_0FDD21E68EF5BCDE02FC2178D162E4E2" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_DeferredRevenueNoncurrent_0FDD21E68EF5BCDE02FC2178D162E4E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_69CD1DF6E73E105749D8215A98768E2E" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_69CD1DF6E73E105749D8215A98768E2E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedLiabilitiesCurrentAndNoncurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrentAndNoncurrent_143B17496E65F5CEE65E216260C2600A" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrentAndNoncurrent_143B17496E65F5CEE65E216260C2600A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredTaxLiabilities" xlink:label="loc_us-gaap_DeferredTaxLiabilities_6B3C9DFDA84D6079620E2162B1F7B6C5" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_DeferredTaxLiabilities_6B3C9DFDA84D6079620E2162B1F7B6C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="loc_us-gaap_SalesRevenueGoodsNet_6D9F94A8B9BCB423FB2D216EC6169BA2" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_SalesRevenueGoodsNet_6D9F94A8B9BCB423FB2D216EC6169BA2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_AFD9A894C78C23D281FB216EC654DBB9" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_CostOfGoodsSold_AFD9A894C78C23D281FB216EC654DBB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNet" xlink:label="loc_us-gaap_AccountsReceivableNet_FF25D053D4E7E94FACDE216F32506ABC" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_AccountsReceivableNet_FF25D053D4E7E94FACDE216F32506ABC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_B88AEF22793A25E5AB4F216FCD35587A" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_Assets_B88AEF22793A25E5AB4F216FCD35587A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_A2E50E6B4843CE294DC821702C4AF519" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_us-gaap_Liabilities_A2E50E6B4843CE294DC821702C4AF519" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Revenuecurrentportionofremainingperformanceobligation" xlink:label="loc_iep_Revenuecurrentportionofremainingperformanceobligation_8ED607E1CA8639788D8E21766B985543" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_iep_Revenuecurrentportionofremainingperformanceobligation_8ED607E1CA8639788D8E21766B985543" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Revenuenoncurrentportionofremainingperformanceobligation" xlink:label="loc_iep_Revenuenoncurrentportionofremainingperformanceobligation_B8E13C0C19630FB643002177107B3DAB" xlink:type="locator" />
    <link:definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_02B98070D26E2CE30E91215A9874C315" xlink:to="loc_iep_Revenuenoncurrentportionofremainingperformanceobligation_B8E13C0C19630FB643002177107B3DAB" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesNotes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended">
    <link:loc xlink:href="iep-20180331.xsd#iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems" xlink:label="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_B9DABDEC6AE070865A52219DC03FDFA9" xlink:type="locator" />
    <link:loc xlink:href="iep-20180331.xsd#iep_OrganizationConsolidationandPresentationofFinancialStatementsTable" xlink:label="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_8AC032B71E971C3F5060219DC03F8D93" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_B9DABDEC6AE070865A52219DC03FDFA9" xlink:to="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_8AC032B71E971C3F5060219DC03F8D93" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_A2461C755BDC18026071219E6AE7D930" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsTable_8AC032B71E971C3F5060219DC03F8D93" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_A2461C755BDC18026071219E6AE7D930" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_C5D2BF441D13AA200ACB219E6CEDC069_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_A2461C755BDC18026071219E6AE7D930" xlink:to="loc_us-gaap_SegmentDomain_C5D2BF441D13AA200ACB219E6CEDC069_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_C5D2BF441D13AA200ACB219E6CEDC069" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_A2461C755BDC18026071219E6AE7D930" xlink:to="loc_us-gaap_SegmentDomain_C5D2BF441D13AA200ACB219E6CEDC069" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_583DAAA6FDFFC9868D8A219E91E611FC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C5D2BF441D13AA200ACB219E6CEDC069" xlink:to="loc_iep_AutomotiveSegmentMember_583DAAA6FDFFC9868D8A219E91E611FC" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_4FE68104169E354FC72321A0C61BADA0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C5D2BF441D13AA200ACB219E6CEDC069" xlink:to="loc_iep_EnergySegmentMember_4FE68104169E354FC72321A0C61BADA0" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RailcarSegmentMember" xlink:label="loc_iep_RailcarSegmentMember_E6D577F1E58443EB85C921A169651E5B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C5D2BF441D13AA200ACB219E6CEDC069" xlink:to="loc_iep_RailcarSegmentMember_E6D577F1E58443EB85C921A169651E5B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_GamingSegmentMember" xlink:label="loc_iep_GamingSegmentMember_CAC2338463FFC33F05E821A1D9933896" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C5D2BF441D13AA200ACB219E6CEDC069" xlink:to="loc_iep_GamingSegmentMember_CAC2338463FFC33F05E821A1D9933896" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationPolicyTextBlock" xlink:label="loc_us-gaap_ConsolidationPolicyTextBlock_618AD7A5190521BA1288215A9ED0AC4A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_B9DABDEC6AE070865A52219DC03FDFA9" xlink:to="loc_us-gaap_ConsolidationPolicyTextBlock_618AD7A5190521BA1288215A9ED0AC4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueOfFinancialInstrumentsPolicy" xlink:label="loc_us-gaap_FairValueOfFinancialInstrumentsPolicy_2A8CE61F88D58B1E1C81215A9ED07200" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_B9DABDEC6AE070865A52219DC03FDFA9" xlink:to="loc_us-gaap_FairValueOfFinancialInstrumentsPolicy_2A8CE61F88D58B1E1C81215A9ED07200" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueRecognitionPolicyTextBlock" xlink:label="loc_us-gaap_RevenueRecognitionPolicyTextBlock_BD2AC4B4868F837C4F64219E3A585BD6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_B9DABDEC6AE070865A52219DC03FDFA9" xlink:to="loc_us-gaap_RevenueRecognitionPolicyTextBlock_BD2AC4B4868F837C4F64219E3A585BD6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_4958ABCA52F8B7B292EF215A9ED01235" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_B9DABDEC6AE070865A52219DC03FDFA9" xlink:to="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_4958ABCA52F8B7B292EF215A9ED01235" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DescriptionOfNewAccountingPronouncementsNotYetAdopted" xlink:label="loc_us-gaap_DescriptionOfNewAccountingPronouncementsNotYetAdopted_68C453DAC36344389A4D215A9ED0CA46" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_OrganizationConsolidationandPresentationofFinancialStatementsLineItems_B9DABDEC6AE070865A52219DC03FDFA9" xlink:to="loc_us-gaap_DescriptionOfNewAccountingPronouncementsNotYetAdopted_68C453DAC36344389A4D215A9ED0CA46" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntityLineItems" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_9F6528C647C35797A40C4CB5DBEF4D28" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_BCE8E4E379FE53A5AC941CE531B49869" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_9F6528C647C35797A40C4CB5DBEF4D28" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_BCE8E4E379FE53A5AC941CE531B49869" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_FAB12F71F5165C92A1F86F2C7605BD40" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_BCE8E4E379FE53A5AC941CE531B49869" xlink:to="loc_dei_LegalEntityAxis_FAB12F71F5165C92A1F86F2C7605BD40" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_84DD99B6B1107AC338A2A913ECF059A4_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_FAB12F71F5165C92A1F86F2C7605BD40" xlink:to="loc_dei_EntityDomain_84DD99B6B1107AC338A2A913ECF059A4_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_265630C7CFB55B16BCE55497C3EB29C5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_FAB12F71F5165C92A1F86F2C7605BD40" xlink:to="loc_dei_EntityDomain_265630C7CFB55B16BCE55497C3EB29C5" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_AD78A31EF3F7588FB0DCBE0ECB932EE6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_265630C7CFB55B16BCE55497C3EB29C5" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_AD78A31EF3F7588FB0DCBE0ECB932EE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTextBlock" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTextBlock_EC676354BE315F36A7AE3614890BABF8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_9F6528C647C35797A40C4CB5DBEF4D28" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTextBlock_EC676354BE315F36A7AE3614890BABF8" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/ChangesInAccumulatedOtherComprehensiveLoss" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/ChangesInAccumulatedOtherComprehensiveLossDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/ChangesInAccumulatedOtherComprehensiveLossTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/CommitmentsAndContingencies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/CommitmentsAndContingenciesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingenciesLineItems" xlink:label="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingenciesTable" xlink:label="loc_us-gaap_LossContingenciesTable_F70B5F605B95599BFF31217A9336743D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_us-gaap_LossContingenciesTable_F70B5F605B95599BFF31217A9336743D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_67E79E382EAE8DA21977217A9336C6CB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_F70B5F605B95599BFF31217A9336743D" xlink:to="loc_dei_LegalEntityAxis_67E79E382EAE8DA21977217A9336C6CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_B9187AE3606DC208EE1A217A9336C4C2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_67E79E382EAE8DA21977217A9336C6CB" xlink:to="loc_dei_EntityDomain_B9187AE3606DC208EE1A217A9336C4C2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_B9187AE3606DC208EE1A217A9336C4C2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_67E79E382EAE8DA21977217A9336C6CB" xlink:to="loc_dei_EntityDomain_B9187AE3606DC208EE1A217A9336C4C2" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesGPMember" xlink:label="loc_iep_IcahnEnterprisesGPMember_45E99DB9147F6DBBFD10217A93364ED9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_B9187AE3606DC208EE1A217A9336C4C2" xlink:to="loc_iep_IcahnEnterprisesGPMember_45E99DB9147F6DBBFD10217A93364ED9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_0AC923E9C0E074D141F1217A9337E2CC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_F70B5F605B95599BFF31217A9336743D" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_0AC923E9C0E074D141F1217A9337E2CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_C2A8218FD4C916FC0C6F217A933784F5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_0AC923E9C0E074D141F1217A9337E2CC" xlink:to="loc_us-gaap_SegmentDomain_C2A8218FD4C916FC0C6F217A933784F5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_C2A8218FD4C916FC0C6F217A933784F5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_0AC923E9C0E074D141F1217A9337E2CC" xlink:to="loc_us-gaap_SegmentDomain_C2A8218FD4C916FC0C6F217A933784F5" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_5AE639B79D043040B369217A93372B51" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C2A8218FD4C916FC0C6F217A933784F5" xlink:to="loc_iep_AutomotiveSegmentMember_5AE639B79D043040B369217A93372B51" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_5A8198C98B97AC66DB7C217A93378625" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C2A8218FD4C916FC0C6F217A933784F5" xlink:to="loc_iep_EnergySegmentMember_5A8198C98B97AC66DB7C217A93378625" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RailcarSegmentMember" xlink:label="loc_iep_RailcarSegmentMember_B282044FD1C6EF111B39217A9338E85E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C2A8218FD4C916FC0C6F217A933784F5" xlink:to="loc_iep_RailcarSegmentMember_B282044FD1C6EF111B39217A9338E85E" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MetalsSegmentMember" xlink:label="loc_iep_MetalsSegmentMember_6E721E5E129E001F1B34217A93381C8C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C2A8218FD4C916FC0C6F217A933784F5" xlink:to="loc_iep_MetalsSegmentMember_6E721E5E129E001F1B34217A93381C8C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AA6FAF27A574AAAA4B24217A93384C25" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_F70B5F605B95599BFF31217A9336743D" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AA6FAF27A574AAAA4B24217A93384C25" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_564A2138938748D8CDDD217A933800ED_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AA6FAF27A574AAAA4B24217A93384C25" xlink:to="loc_us-gaap_RelatedPartyDomain_564A2138938748D8CDDD217A933800ED_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_564A2138938748D8CDDD217A933800ED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AA6FAF27A574AAAA4B24217A93384C25" xlink:to="loc_us-gaap_RelatedPartyDomain_564A2138938748D8CDDD217A933800ED" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_StarfireHoldingCorporationMember" xlink:label="loc_iep_StarfireHoldingCorporationMember_7BA6418D82F3E374AEAD217A933853DE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_564A2138938748D8CDDD217A933800ED" xlink:to="loc_iep_StarfireHoldingCorporationMember_7BA6418D82F3E374AEAD217A933853DE" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MembersOrPartnersAxis" xlink:label="loc_iep_MembersOrPartnersAxis_8571A3645E00A0840B8D217A93398991" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_F70B5F605B95599BFF31217A9336743D" xlink:to="loc_iep_MembersOrPartnersAxis_8571A3645E00A0840B8D217A93398991" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PartnerNameDomain" xlink:label="loc_iep_PartnerNameDomain_81941F388A19ACA87945217A9339EF4C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_iep_MembersOrPartnersAxis_8571A3645E00A0840B8D217A93398991" xlink:to="loc_iep_PartnerNameDomain_81941F388A19ACA87945217A9339EF4C_default" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PartnerNameDomain" xlink:label="loc_iep_PartnerNameDomain_81941F388A19ACA87945217A9339EF4C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_iep_MembersOrPartnersAxis_8571A3645E00A0840B8D217A93398991" xlink:to="loc_iep_PartnerNameDomain_81941F388A19ACA87945217A9339EF4C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PrincipalOwnersAndAffiliatesMember" xlink:label="loc_iep_PrincipalOwnersAndAffiliatesMember_71FA5A660393C5F1BC79217A93398E0F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_PartnerNameDomain_81941F388A19ACA87945217A9339EF4C" xlink:to="loc_iep_PrincipalOwnersAndAffiliatesMember_71FA5A660393C5F1BC79217A93398E0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccrualForEnvironmentalLossContingencies" xlink:label="loc_us-gaap_AccrualForEnvironmentalLossContingencies_EAC442680F10A4437D1F217A9339E24E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_us-gaap_AccrualForEnvironmentalLossContingencies_EAC442680F10A4437D1F217A9339E24E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SiteContingencyLossExposureInExcessOfAccrualBestEstimate" xlink:label="loc_us-gaap_SiteContingencyLossExposureInExcessOfAccrualBestEstimate_1D93AEF90B5A1CB68B39217A933A5C90" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_us-gaap_SiteContingencyLossExposureInExcessOfAccrualBestEstimate_1D93AEF90B5A1CB68B39217A933A5C90" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EnvironmentalRemediationExpense" xlink:label="loc_us-gaap_EnvironmentalRemediationExpense_20644FEA76C0D9859BEF217A933A46A8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_us-gaap_EnvironmentalRemediationExpense_20644FEA76C0D9859BEF217A933A46A8" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_CostofRINs" xlink:label="loc_iep_CostofRINs_BF53D85D43567358D93A217A933A1EE9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_iep_CostofRINs_BF53D85D43567358D93A217A933A1EE9" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Biofuelblendingobligation" xlink:label="loc_iep_Biofuelblendingobligation_3604D52BD4A573755035217A933A07E8" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_iep_Biofuelblendingobligation_3604D52BD4A573755035217A933A07E8" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RINsasset" xlink:label="loc_iep_RINsasset_41762AB1DCB71DC4813A217AFF230901" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_iep_RINsasset_41762AB1DCB71DC4813A217AFF230901" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingencyAccrualAtCarryingValue" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_06EE8364151DC52C30DB217A933AD91E" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_us-gaap_LossContingencyAccrualAtCarryingValue_06EE8364151DC52C30DB217A933AD91E" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AffiliateOwnershipInParentCompanyGeneralPartner" xlink:label="loc_iep_AffiliateOwnershipInParentCompanyGeneralPartner_10FC2644EB7F0F1A2091217A933A0D02" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_iep_AffiliateOwnershipInParentCompanyGeneralPartner_10FC2644EB7F0F1A2091217A933A0D02" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_259D617DC1DF3FACA088217A933AACBB" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_259D617DC1DF3FACA088217A933AACBB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_659D8DE1E68112DB81E6217A933A8171" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_659D8DE1E68112DB81E6217A933A8171" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_OwnershipPercentageByPrincipalOwner" xlink:label="loc_iep_OwnershipPercentageByPrincipalOwner_EA05AE216EA429EB2FE6217A933AE4B8" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_iep_OwnershipPercentageByPrincipalOwner_EA05AE216EA429EB2FE6217A933AE4B8" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_SubsidiaryIndemnityAgreementPensionFundingContingenciesAsResultOfBeingInControlledGroupDistributionLimitationNetWorthFloor" xlink:label="loc_iep_SubsidiaryIndemnityAgreementPensionFundingContingenciesAsResultOfBeingInControlledGroupDistributionLimitationNetWorthFloor_B48135DEB39D819FE908217A933B2B02" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_F7882531886A7611FE03217A9339AA52" xlink:to="loc_iep_SubsidiaryIndemnityAgreementPensionFundingContingenciesAsResultOfBeingInControlledGroupDistributionLimitationNetWorthFloor_B48135DEB39D819FE908217A933B2B02" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/CondensedBalanceSheetsByReportingSegmentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B185EBF70A115E0FBD9B49D83CC0563C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_C7C34D22EE945B53B03534B33FF3F33B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B185EBF70A115E0FBD9B49D83CC0563C" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_C7C34D22EE945B53B03534B33FF3F33B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_A0DB057DF3EA5B5EB1E55E74A2E82C72" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_C7C34D22EE945B53B03534B33FF3F33B" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_A0DB057DF3EA5B5EB1E55E74A2E82C72" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_8D46A935D6E3C6EC5793A913EAF6A1F9_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_A0DB057DF3EA5B5EB1E55E74A2E82C72" xlink:to="loc_us-gaap_SegmentDomain_8D46A935D6E3C6EC5793A913EAF6A1F9_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_A0DB057DF3EA5B5EB1E55E74A2E82C72" xlink:to="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InvestmentSegmentMember" xlink:label="loc_iep_InvestmentSegmentMember_E7389DA65B9058AB87068A64E85A3325" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_InvestmentSegmentMember_E7389DA65B9058AB87068A64E85A3325" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_89D2081A5E975387BF1ED66C18C3A804" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_AutomotiveSegmentMember_89D2081A5E975387BF1ED66C18C3A804" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_1D4DCCAEEEF45893A4F4E0E5CE453545" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_EnergySegmentMember_1D4DCCAEEEF45893A4F4E0E5CE453545" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RailcarSegmentMember" xlink:label="loc_iep_RailcarSegmentMember_D66CB10737CE5465B7D96132037A800B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_RailcarSegmentMember_D66CB10737CE5465B7D96132037A800B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_GamingSegmentMember" xlink:label="loc_iep_GamingSegmentMember_9875453FF7905D1CA8B653693766C3C4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_GamingSegmentMember_9875453FF7905D1CA8B653693766C3C4" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MetalsSegmentMember" xlink:label="loc_iep_MetalsSegmentMember_9ECE0FAEA6155E17A51EBC2230BF8C6D" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_MetalsSegmentMember_9ECE0FAEA6155E17A51EBC2230BF8C6D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MiningsegmentMember" xlink:label="loc_iep_MiningsegmentMember_59A15141CEC65A8EA593C5624244DA8A" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_MiningsegmentMember_59A15141CEC65A8EA593C5624244DA8A" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FoodPackagingSegmentMember" xlink:label="loc_iep_FoodPackagingSegmentMember_D789053EFEB15ECCBFE746A06724882D" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_FoodPackagingSegmentMember_D789053EFEB15ECCBFE746A06724882D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RealEstateSegmentMember" xlink:label="loc_iep_RealEstateSegmentMember_F889BE8CE8A5527C89C78C70CE67425E" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_RealEstateSegmentMember_F889BE8CE8A5527C89C78C70CE67425E" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_HomeFashionSegmentMember" xlink:label="loc_iep_HomeFashionSegmentMember_8F6A3177C97A5341ACDEE6911AB93CF8" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_HomeFashionSegmentMember_8F6A3177C97A5341ACDEE6911AB93CF8" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_HoldingCompanyMember" xlink:label="loc_iep_HoldingCompanyMember_D3617224E48C53C1BEC4386BB1B0A1BB" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0067BB6F69FB59BEA39070DCB908277C" xlink:to="loc_iep_HoldingCompanyMember_D3617224E48C53C1BEC4386BB1B0A1BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B185EBF70A115E0FBD9B49D83CC0563C" xlink:to="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_78F0BE6FFE4F55B5B57C2FD8EE5BB2C8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_78F0BE6FFE4F55B5B57C2FD8EE5BB2C8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalents" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents_2E9F145750E95959AC58C979CCE1C9D8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalents_2E9F145750E95959AC58C979CCE1C9D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Investments" xlink:label="loc_us-gaap_Investments_EC0D2B2459DB5CE49950AAF1B692CA4F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:to="loc_us-gaap_Investments_EC0D2B2459DB5CE49950AAF1B692CA4F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNet" xlink:label="loc_us-gaap_AccountsReceivableNet_FB5A73267C02584985C39A43A40BBD05" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:to="loc_us-gaap_AccountsReceivableNet_FB5A73267C02584985C39A43A40BBD05" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_74F8CC6E049C53868B8EEDF59AA93D25" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:to="loc_us-gaap_InventoryNet_74F8CC6E049C53868B8EEDF59AA93D25" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_4E806EE339EC55CF8033C3AE32188B1E" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_4E806EE339EC55CF8033C3AE32188B1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetIncludingGoodwill_E480697C7FBD539B9C9E784AF220299D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:to="loc_us-gaap_IntangibleAssetsNetIncludingGoodwill_E480697C7FBD539B9C9E784AF220299D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_OtherAssetsAndDueFromCorrespondentBrokers" xlink:label="loc_iep_OtherAssetsAndDueFromCorrespondentBrokers_994B73D7FB7E5E6280B9FEDE41239B3F" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:to="loc_iep_OtherAssetsAndDueFromCorrespondentBrokers_994B73D7FB7E5E6280B9FEDE41239B3F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_9188127B46D552B09AF6B3D17314D3E4" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_2080D1C334515C76A90DF1A5F2187AA1" xlink:to="loc_us-gaap_Assets_9188127B46D552B09AF6B3D17314D3E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B185EBF70A115E0FBD9B49D83CC0563C" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_F0B7C3F77EAD53EDA29D91AF20E6C872" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_F0B7C3F77EAD53EDA29D91AF20E6C872" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue" xlink:label="loc_us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue_7919F85B2A99539D8D715CA02BA5A844" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue_7919F85B2A99539D8D715CA02BA5A844" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToCorrespondentBrokers" xlink:label="loc_us-gaap_DueToCorrespondentBrokers_322BCB699B5051E4842173E6FB39C903" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_DueToCorrespondentBrokers_322BCB699B5051E4842173E6FB39C903" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PostemploymentBenefitsLiabilityCurrentAndNoncurrent" xlink:label="loc_us-gaap_PostemploymentBenefitsLiabilityCurrentAndNoncurrent_556432FD63385BD0A008FFF1B38471BC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_PostemploymentBenefitsLiabilityCurrentAndNoncurrent_556432FD63385BD0A008FFF1B38471BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtAndCapitalLeaseObligations" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_F7DFB549C844552BB8F247EE854FA96C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_F7DFB549C844552BB8F247EE854FA96C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_D59AF133B5445D0C8803E0B4B7319269" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_Liabilities_D59AF133B5445D0C8803E0B4B7319269" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_E3456B8CBA7C5370911D8A2009A2CD19" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_StockholdersEquity_E3456B8CBA7C5370911D8A2009A2CD19" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaap_MinorityInterest_0ADA5AF2C6E2528286BB40E0D4C45617" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_MinorityInterest_0ADA5AF2C6E2528286BB40E0D4C45617" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_75E5E06CABAA5112B902EEE16892ECC0" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_75E5E06CABAA5112B902EEE16892ECC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_20A0E1609D7954E3A03FDD13F5400297" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_74CDADB3A2575DC3A75EE9A6E83C70B6" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_20A0E1609D7954E3A03FDD13F5400297" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/CondensedConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_9C5879D745400E54E36DE56A36063633" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_7D08F0E27AAE890353FCE56A36050040" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_9C5879D745400E54E36DE56A36063633" xlink:to="loc_us-gaap_StatementTable_7D08F0E27AAE890353FCE56A36050040" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_4070831BB9D8EDA73B3DE56A3606E4A5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_7D08F0E27AAE890353FCE56A36050040" xlink:to="loc_dei_LegalEntityAxis_4070831BB9D8EDA73B3DE56A3606E4A5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_2D891D7E89724CACF962E56A3606F44B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_4070831BB9D8EDA73B3DE56A3606E4A5" xlink:to="loc_dei_EntityDomain_2D891D7E89724CACF962E56A3606F44B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_2D891D7E89724CACF962E56A3606F44B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_4070831BB9D8EDA73B3DE56A3606E4A5" xlink:to="loc_dei_EntityDomain_2D891D7E89724CACF962E56A3606F44B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_C7CFCF78228F9CB22836E56A36067E30" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_2D891D7E89724CACF962E56A3606F44B" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_C7CFCF78228F9CB22836E56A36067E30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9C5879D745400E54E36DE56A36063633" xlink:to="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_5B1B6BD9B6FDE14D94DAE56A3606D372" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_5B1B6BD9B6FDE14D94DAE56A3606D372" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalents" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents_AA86E32AF6C6AA7C50CAE56A36076B70" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalents_AA86E32AF6C6AA7C50CAE56A36076B70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Investments" xlink:label="loc_us-gaap_Investments_B8AC45CA068E0B469B6AE56A3607F24E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_Investments_B8AC45CA068E0B469B6AE56A3607F24E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueFromCorrespondentBrokers" xlink:label="loc_us-gaap_DueFromCorrespondentBrokers_AF8998B2BC48FF0EECD6E56A3607A670" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_DueFromCorrespondentBrokers_AF8998B2BC48FF0EECD6E56A3607A670" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNet" xlink:label="loc_us-gaap_AccountsReceivableNet_29A59C68106927D15BBEE56A36083A2E" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_AccountsReceivableNet_29A59C68106927D15BBEE56A36083A2E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_388FC4B4F9EF30F94058E56A3608442B" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_InventoryNet_388FC4B4F9EF30F94058E56A3608442B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_33E040EBA27B3EAAB56AE56A3608E1D9" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_33E040EBA27B3EAAB56AE56A3608E1D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_906C4F6171874FA8095BE56A3608E5BE" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_Goodwill_906C4F6171874FA8095BE56A3608E5BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_EBC82FB6F6FE415A829CE56A36090E99" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_EBC82FB6F6FE415A829CE56A36090E99" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaap_OtherAssets_143FFF2CA14BC104A4B6E56A3609F4C3" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_OtherAssets_143FFF2CA14BC104A4B6E56A3609F4C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_82FB09C029964B126C20E56A36096B23" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_71023F1279C0A6997E6AE56A3606039B" xlink:to="loc_us-gaap_Assets_82FB09C029964B126C20E56A36096B23" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9C5879D745400E54E36DE56A36063633" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableCurrentAndNoncurrent" xlink:label="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_6E38474056B7B7D646FCE56A36099451" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_6E38474056B7B7D646FCE56A36099451" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedLiabilitiesCurrentAndNoncurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrentAndNoncurrent_58AA7168AAA67F2AF83AE56A36091805" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrentAndNoncurrent_58AA7168AAA67F2AF83AE56A36091805" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredTaxLiabilities" xlink:label="loc_us-gaap_DeferredTaxLiabilities_2DE2714EE6F3CE21ED18E56A360945BF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_DeferredTaxLiabilities_2DE2714EE6F3CE21ED18E56A360945BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaap_DerivativeLiabilities_B9C99C5BF856D6502468E56A360ABB48" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_DerivativeLiabilities_B9C99C5BF856D6502468E56A360ABB48" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue" xlink:label="loc_us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue_65991A218098F11564E0E56A360A0A68" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue_65991A218098F11564E0E56A360A0A68" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToCorrespondentBrokers" xlink:label="loc_us-gaap_DueToCorrespondentBrokers_F0645F02D01335556EA9E56A360ACE1C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_DueToCorrespondentBrokers_F0645F02D01335556EA9E56A360ACE1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PostemploymentBenefitsLiabilityCurrentAndNoncurrent" xlink:label="loc_us-gaap_PostemploymentBenefitsLiabilityCurrentAndNoncurrent_9F31854ADE78D88FE9CCE56A360AAE60" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_PostemploymentBenefitsLiabilityCurrentAndNoncurrent_9F31854ADE78D88FE9CCE56A360AAE60" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtAndCapitalLeaseObligations" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_B6B9AC3AAB754F8A7EF4E56A360A6A28" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_B6B9AC3AAB754F8A7EF4E56A360A6A28" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_DCBC5591C87CB6E2B22AE56A360A9C32" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_Liabilities_DCBC5591C87CB6E2B22AE56A360A9C32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_0CFBA062A234017AEC0AE56A360A1A7D" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_CommitmentsAndContingencies_0CFBA062A234017AEC0AE56A360A1A7D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_45BC075ECC7C4052C9CBE56A360B6588" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_45BC075ECC7C4052C9CBE56A360B6588" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LimitedPartnersCapitalAccount" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccount_D3DA4F1A40EF5F35E937E56A360BD96D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_45BC075ECC7C4052C9CBE56A360B6588" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccount_D3DA4F1A40EF5F35E937E56A360BD96D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralPartnersCapitalAccount" xlink:label="loc_us-gaap_GeneralPartnersCapitalAccount_4EA3F81326BA1D576CF4E56A360B8D32" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_45BC075ECC7C4052C9CBE56A360B6588" xlink:to="loc_us-gaap_GeneralPartnersCapitalAccount_4EA3F81326BA1D576CF4E56A360B8D32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_1A1EA788AE69968E7353E56A360BE60F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_45BC075ECC7C4052C9CBE56A360B6588" xlink:to="loc_us-gaap_StockholdersEquity_1A1EA788AE69968E7353E56A360BE60F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaap_MinorityInterest_3D232244A8CBCEA6F62BE56A360B4F14" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_45BC075ECC7C4052C9CBE56A360B6588" xlink:to="loc_us-gaap_MinorityInterest_3D232244A8CBCEA6F62BE56A360B4F14" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_353F4B7182BF51413E1BE56A360BB1CA" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_45BC075ECC7C4052C9CBE56A360B6588" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_353F4B7182BF51413E1BE56A360BB1CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_86D211F2C32CE27E7148E56A360BE4A4" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_F4135C0786C2524293A7E56A360983FD" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_86D211F2C32CE27E7148E56A360BE4A4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/CondensedConsolidatedBalanceSheetsParentheticals" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/CondensedConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_0AB396F9B7478D3C2897F92DB91FC0B8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:to="loc_us-gaap_StatementTable_0AB396F9B7478D3C2897F92DB91FC0B8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_CB50209E39E55E971B9FF92DB91F40AC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0AB396F9B7478D3C2897F92DB91FC0B8" xlink:to="loc_dei_LegalEntityAxis_CB50209E39E55E971B9FF92DB91F40AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_71A64AC7C8C8E00EBEDAF92DB91F5D71_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_CB50209E39E55E971B9FF92DB91F40AC" xlink:to="loc_dei_EntityDomain_71A64AC7C8C8E00EBEDAF92DB91F5D71_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_71A64AC7C8C8E00EBEDAF92DB91F5D71" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_CB50209E39E55E971B9FF92DB91F40AC" xlink:to="loc_dei_EntityDomain_71A64AC7C8C8E00EBEDAF92DB91F5D71" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_3FEF520ED90CFCC0F87EF92DB91FF29C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_71A64AC7C8C8E00EBEDAF92DB91F5D71" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_3FEF520ED90CFCC0F87EF92DB91FF29C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Proceedsfromsubsidiaryequityissuance" xlink:label="loc_iep_Proceedsfromsubsidiaryequityissuance_F4B6A22030363156C62BF932D0B08437" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:to="loc_iep_Proceedsfromsubsidiaryequityissuance_F4B6A22030363156C62BF932D0B08437" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_94DBB66F3E3D9B670169F92DB92021C7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_94DBB66F3E3D9B670169F92DB92021C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_0AA0F91C9780D00B3E01F92DB9209EBE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_94DBB66F3E3D9B670169F92DB92021C7" xlink:to="loc_us-gaap_ProfitLoss_0AA0F91C9780D00B3E01F92DB9209EBE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_94DBB66F3E3D9B670169F92DB92021C7" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainLossOnInvestments" xlink:label="loc_us-gaap_GainLossOnInvestments_F104B61331FA1C55B846F92DB920819E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_us-gaap_GainLossOnInvestments_F104B61331FA1C55B846F92DB920819E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireMarketableSecurities" xlink:label="loc_us-gaap_PaymentsToAcquireMarketableSecurities_24B350442317D09465EBF92DB9206EB7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_us-gaap_PaymentsToAcquireMarketableSecurities_24B350442317D09465EBF92DB9206EB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities" xlink:label="loc_us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_888A1B3F9A9CFB9B7649F92DB9206C48" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_888A1B3F9A9CFB9B7649F92DB9206C48" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PurchasesToCoverSecuritiesSoldNotYetPurchased" xlink:label="loc_iep_PurchasesToCoverSecuritiesSoldNotYetPurchased_638294A0E895E2FD91E5F92DB9217069" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_iep_PurchasesToCoverSecuritiesSoldNotYetPurchased_638294A0E895E2FD91E5F92DB9217069" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentSoldNotYetPurchasedSaleProceeds" xlink:label="loc_us-gaap_InvestmentSoldNotYetPurchasedSaleProceeds_28E44FF1CA345535DBE6F92DB9215D18" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_us-gaap_InvestmentSoldNotYetPurchasedSaleProceeds_28E44FF1CA345535DBE6F92DB9215D18" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet" xlink:label="loc_us-gaap_IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet_C1C71F16637650CAC803F92DB921C105" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_us-gaap_IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet_C1C71F16637650CAC803F92DB921C105" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_DepreciationAndAmortizationIncludingNonCashInterestExpense" xlink:label="loc_iep_DepreciationAndAmortizationIncludingNonCashInterestExpense_7B1DCD79137495C87E7DF92DB921D250" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_iep_DepreciationAndAmortizationIncludingNonCashInterestExpense_7B1DCD79137495C87E7DF92DB921D250" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetImpairmentCharges" xlink:label="loc_us-gaap_AssetImpairmentCharges_66D808734C935C840428F92DB921ABB1" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_us-gaap_AssetImpairmentCharges_66D808734C935C840428F92DB921ABB1" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Equityearningsfromnonconsolidatedaffiliates" xlink:label="loc_iep_Equityearningsfromnonconsolidatedaffiliates_498EB1DE7B1F29F1C37CF92DB9210A8C" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_iep_Equityearningsfromnonconsolidatedaffiliates_498EB1DE7B1F29F1C37CF92DB9210A8C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredIncomeTaxes" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_4E9FB95EC303C4A76404F92DB92126E7" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_4E9FB95EC303C4A76404F92DB92126E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherOperatingActivitiesCashFlowStatement" xlink:label="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_01CDBB7FAB686A7D43D7F92DB922313F" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_01CDBB7FAB686A7D43D7F92DB922313F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_982E496BA34CD25B0FA0F92DB92248F1" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_3BEAC0206972567F9274F92DB9204645" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_982E496BA34CD25B0FA0F92DB92248F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_1C85CCB2BD63D305791CF92DB922668A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_94DBB66F3E3D9B670169F92DB92021C7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_1C85CCB2BD63D305791CF92DB922668A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_3601F956588BD0D006E6F92DB922E38E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_3601F956588BD0D006E6F92DB922E38E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireProductiveAssets" xlink:label="loc_us-gaap_PaymentsToAcquireProductiveAssets_88EAC55A4581E4DFB4FCF92DB9229F69" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_3601F956588BD0D006E6F92DB922E38E" xlink:to="loc_us-gaap_PaymentsToAcquireProductiveAssets_88EAC55A4581E4DFB4FCF92DB9229F69" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_1217280294EE71DD05D9F92DB9227C5B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_3601F956588BD0D006E6F92DB922E38E" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_1217280294EE71DD05D9F92DB9227C5B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries" xlink:label="loc_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries_571FCD37DFE45EAC85A2F92DB9224665" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_3601F956588BD0D006E6F92DB922E38E" xlink:to="loc_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries_571FCD37DFE45EAC85A2F92DB9224665" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets" xlink:label="loc_us-gaap_ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets_62A30B670520AF722C79F92DB924DE8F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_3601F956588BD0D006E6F92DB922E38E" xlink:to="loc_us-gaap_ProceedsFromSalesOfBusinessAffiliateAndProductiveAssets_62A30B670520AF722C79F92DB924DE8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_255484B70C173BCF1658F92DB924C5EF" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_3601F956588BD0D006E6F92DB922E38E" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_255484B70C173BCF1658F92DB924C5EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_981A30B338ADD245BB83F92DB9246E2A" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_3601F956588BD0D006E6F92DB922E38E" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_981A30B338ADD245BB83F92DB9246E2A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ProceedsfromInvestmentsegmentcontributions" xlink:label="loc_iep_ProceedsfromInvestmentsegmentcontributions_8087D8217C9AFDCBBD51F92DB924EA1E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:to="loc_iep_ProceedsfromInvestmentsegmentcontributions_8087D8217C9AFDCBBD51F92DB924EA1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromPartnershipContribution" xlink:label="loc_us-gaap_ProceedsFromPartnershipContribution_B34265AFB7043C6EA348F92DB9249EE7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:to="loc_us-gaap_ProceedsFromPartnershipContribution_B34265AFB7043C6EA348F92DB9249EE7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToMinorityShareholders" xlink:label="loc_us-gaap_PaymentsToMinorityShareholders_FF78AFAF36E6F591A93FF92DB925B8F8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:to="loc_us-gaap_PaymentsToMinorityShareholders_FF78AFAF36E6F591A93FF92DB925B8F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfUnsecuredDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfUnsecuredDebt_F34D5407DCFE51A8C07FF92DB925C633" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfUnsecuredDebt_F34D5407DCFE51A8C07FF92DB925C633" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepaymentsOfUnsecuredDebt" xlink:label="loc_us-gaap_RepaymentsOfUnsecuredDebt_DE8BAC62CF4994D12F58F92DB925BDB3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:to="loc_us-gaap_RepaymentsOfUnsecuredDebt_DE8BAC62CF4994D12F58F92DB925BDB3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromOtherDebt" xlink:label="loc_us-gaap_ProceedsFromOtherDebt_BB86B841B9592CEAF74FF92DB925CB9C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:to="loc_us-gaap_ProceedsFromOtherDebt_BB86B841B9592CEAF74FF92DB925CB9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepaymentsOfDebtAndCapitalLeaseObligations" xlink:label="loc_us-gaap_RepaymentsOfDebtAndCapitalLeaseObligations_70179A17A2A750A9BCCFF92DB92537ED" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:to="loc_us-gaap_RepaymentsOfDebtAndCapitalLeaseObligations_70179A17A2A750A9BCCFF92DB92537ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" xlink:label="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_73A900FB695DC519E3D0F92DB9250FBD" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:to="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_73A900FB695DC519E3D0F92DB9250FBD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_6999460D0DE626DD3D73F92DB9257819" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_AC8D408C78E20AFFCB41F92DB924D236" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_6999460D0DE626DD3D73F92DB9257819" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_F640051F602781985601F92DB925B8C8" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_F640051F602781985601F92DB925B8C8" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_NetChangeInCashOfAssetsHeldForSale" xlink:label="loc_iep_NetChangeInCashOfAssetsHeldForSale_1FF81AB9F711307F4AC9F92DB926BD7E" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:to="loc_iep_NetChangeInCashOfAssetsHeldForSale_1FF81AB9F711307F4AC9F92DB926BD7E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_E9D7197E4F48A35A3C0EF92DB926D8F2" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_E9D7197E4F48A35A3C0EF92DB926D8F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_BD7AE8717E27892CFC17F92DB9262C28" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2303524BECAD858A8895F92DB920CE90" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_BD7AE8717E27892CFC17F92DB9262C28" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/CondensedConsolidatedStatementsOfChangesInEquity" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_7D99062D1A44964DB508E4B24CAFC543" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_21EE7EE72BB78A2DE5CDE4B24C9F2542" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_7D99062D1A44964DB508E4B24CAFC543" xlink:to="loc_us-gaap_StatementTable_21EE7EE72BB78A2DE5CDE4B24C9F2542" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_7B53278B0291692C0334E4B24C9F6BBA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_21EE7EE72BB78A2DE5CDE4B24C9F2542" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_7B53278B0291692C0334E4B24C9F6BBA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_4E0EE992CB93115F0E16E4B24C9F9028_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_7B53278B0291692C0334E4B24C9F6BBA" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_4E0EE992CB93115F0E16E4B24C9F9028_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_4E0EE992CB93115F0E16E4B24C9F9028" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_7B53278B0291692C0334E4B24C9F6BBA" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_4E0EE992CB93115F0E16E4B24C9F9028" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralPartnerMember" xlink:label="loc_us-gaap_GeneralPartnerMember_FA71F5463A3D02DAA40BE4B24C9F31B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_4E0EE992CB93115F0E16E4B24C9F9028" xlink:to="loc_us-gaap_GeneralPartnerMember_FA71F5463A3D02DAA40BE4B24C9F31B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_50DF963700FFECEA5603E4B24C9F1F3F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_4E0EE992CB93115F0E16E4B24C9F9028" xlink:to="loc_us-gaap_LimitedPartnerMember_50DF963700FFECEA5603E4B24C9F1F3F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ParentMember" xlink:label="loc_us-gaap_ParentMember_727EAFEC33536BF11F8AE4B24C9FB795" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_4E0EE992CB93115F0E16E4B24C9F9028" xlink:to="loc_us-gaap_ParentMember_727EAFEC33536BF11F8AE4B24C9FB795" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_E2315DEBBA4A3635609FE4B24C9F3EB7" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_4E0EE992CB93115F0E16E4B24C9F9028" xlink:to="loc_us-gaap_NoncontrollingInterestMember_E2315DEBBA4A3635609FE4B24C9F3EB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_C91342B4F61885F66E39E4B24CAF976B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_21EE7EE72BB78A2DE5CDE4B24C9F2542" xlink:to="loc_dei_LegalEntityAxis_C91342B4F61885F66E39E4B24CAF976B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_56A42A560FA4A9CC7A5FE4B24CAFFA76_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_C91342B4F61885F66E39E4B24CAF976B" xlink:to="loc_dei_EntityDomain_56A42A560FA4A9CC7A5FE4B24CAFFA76_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_56A42A560FA4A9CC7A5FE4B24CAFFA76" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_C91342B4F61885F66E39E4B24CAF976B" xlink:to="loc_dei_EntityDomain_56A42A560FA4A9CC7A5FE4B24CAFFA76" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_67271730879487324472E4B24CAF5612" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_56A42A560FA4A9CC7A5FE4B24CAFFA76" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_67271730879487324472E4B24CAF5612" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInPartnersCapitalRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7D99062D1A44964DB508E4B24CAFC543" xlink:to="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_61045F48B50501DF34C2E4B24CAF8076" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_61045F48B50501DF34C2E4B24CAF8076" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_B051E3784CD2A2035E69E4B24CAFFDC1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:to="loc_us-gaap_ProfitLoss_B051E3784CD2A2035E69E4B24CAFFDC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_09D5DA510A9EE8D5A1B7E4B24CAFC1DF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_09D5DA510A9EE8D5A1B7E4B24CAFC1DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnersCapitalAccountDistributions" xlink:label="loc_us-gaap_PartnersCapitalAccountDistributions_B20445F935DC08CF00B8E4B24CAFB352" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:to="loc_us-gaap_PartnersCapitalAccountDistributions_B20445F935DC08CF00B8E4B24CAFB352" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnersCapitalAccountContributions" xlink:label="loc_us-gaap_PartnersCapitalAccountContributions_0E08C471BD976DEEE378E4B24CAFA727" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:to="loc_us-gaap_PartnersCapitalAccountContributions_0E08C471BD976DEEE378E4B24CAFA727" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Investmentsegmentcontributions" xlink:label="loc_iep_Investmentsegmentcontributions_7C18698496CC6A9B5DF4E4B24CAFF631" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:to="loc_iep_Investmentsegmentcontributions_7C18698496CC6A9B5DF4E4B24CAFF631" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToMinorityShareholders" xlink:label="loc_us-gaap_PaymentsToMinorityShareholders_B19CE9256F11B8263287E4B24CAFA53C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:to="loc_us-gaap_PaymentsToMinorityShareholders_B19CE9256F11B8263287E4B24CAFA53C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1" xlink:label="loc_us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1_A6B8092AFCE81FD5A27FE4B24CAFBDDE" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:to="loc_us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1_A6B8092AFCE81FD5A27FE4B24CAFBDDE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityOther" xlink:label="loc_us-gaap_StockholdersEquityOther_0C32D16D121EA985D695E4B24CAF07CD" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInPartnersCapitalRollForward_1DE444D27F4EE3D8B4B9E4B24CAF7363" xlink:to="loc_us-gaap_StockholdersEquityOther_0C32D16D121EA985D695E4B24CAF07CD" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/CondensedConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_DEEEB64ECE25CDF49573E4B0F665538E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_2C12B2C8232BDF07CBCCE4B0F65EE4DB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_DEEEB64ECE25CDF49573E4B0F665538E" xlink:to="loc_us-gaap_StatementTable_2C12B2C8232BDF07CBCCE4B0F65EE4DB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_E8303E6E91CDD4F9537AE4B0F65FC986" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2C12B2C8232BDF07CBCCE4B0F65EE4DB" xlink:to="loc_dei_LegalEntityAxis_E8303E6E91CDD4F9537AE4B0F65FC986" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_8BD71CC47FF6D3423B71E4B0F65F163B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_E8303E6E91CDD4F9537AE4B0F65FC986" xlink:to="loc_dei_EntityDomain_8BD71CC47FF6D3423B71E4B0F65F163B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_8BD71CC47FF6D3423B71E4B0F65F163B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_E8303E6E91CDD4F9537AE4B0F65FC986" xlink:to="loc_dei_EntityDomain_8BD71CC47FF6D3423B71E4B0F65F163B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_C56D1FB9E4230127C4D1E4B0F65FD4E9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_8BD71CC47FF6D3423B71E4B0F65F163B" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_C56D1FB9E4230127C4D1E4B0F65FD4E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_D69F53EBC663D6B0ED52E4B0F65F2555" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2C12B2C8232BDF07CBCCE4B0F65EE4DB" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_D69F53EBC663D6B0ED52E4B0F65F2555" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_FEE1D687AC7B8050DCB6E4B0F65F6E92_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_D69F53EBC663D6B0ED52E4B0F65F2555" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_FEE1D687AC7B8050DCB6E4B0F65F6E92_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_FEE1D687AC7B8050DCB6E4B0F65F6E92" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_D69F53EBC663D6B0ED52E4B0F65F2555" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_FEE1D687AC7B8050DCB6E4B0F65F6E92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="loc_us-gaap_LimitedPartnerMember_FB2093393F6DD65B8285E4B0F65F8A78" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_FEE1D687AC7B8050DCB6E4B0F65F6E92" xlink:to="loc_us-gaap_LimitedPartnerMember_FB2093393F6DD65B8285E4B0F65F8A78" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralPartnerMember" xlink:label="loc_us-gaap_GeneralPartnerMember_9FD461A64F99A385FF12E4B0F664E7B6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_FEE1D687AC7B8050DCB6E4B0F65F6E92" xlink:to="loc_us-gaap_GeneralPartnerMember_9FD461A64F99A385FF12E4B0F664E7B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_766FABA470E8786C2D65E4B0F666860B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_DEEEB64ECE25CDF49573E4B0F665538E" xlink:to="loc_us-gaap_ProfitLoss_766FABA470E8786C2D65E4B0F666860B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_0B5362551208681B53A3E4B0F666C2DB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_DEEEB64ECE25CDF49573E4B0F665538E" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_0B5362551208681B53A3E4B0F666C2DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_B45ACC04B97E2D951682E4B0F6660E70" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_0B5362551208681B53A3E4B0F666C2DB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_B45ACC04B97E2D951682E4B0F6660E70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_A0C34FB75AEB1700248DE4B0F6663A8B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_0B5362551208681B53A3E4B0F666C2DB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_A0C34FB75AEB1700248DE4B0F6663A8B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_OtherComprehensiveIncomeTranslationAdjustmentsAndOtherChangesInOtherComprehensiveIncome" xlink:label="loc_iep_OtherComprehensiveIncomeTranslationAdjustmentsAndOtherChangesInOtherComprehensiveIncome_66150EE38DFF14326D20E4B0F6661703" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_0B5362551208681B53A3E4B0F666C2DB" xlink:to="loc_iep_OtherComprehensiveIncomeTranslationAdjustmentsAndOtherChangesInOtherComprehensiveIncome_66150EE38DFF14326D20E4B0F6661703" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_90F76A10AF0B1B8C09A1E4B0F667EACC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_0B5362551208681B53A3E4B0F666C2DB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_90F76A10AF0B1B8C09A1E4B0F667EACC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_F06DB60504C461FD38EBE4B0F6675A83" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_DEEEB64ECE25CDF49573E4B0F665538E" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_F06DB60504C461FD38EBE4B0F6675A83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_0810F4EEF7E02FFAEADFE4B0F6670176" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_DEEEB64ECE25CDF49573E4B0F665538E" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_0810F4EEF7E02FFAEADFE4B0F6670176" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_EAD69F4258CC8C7CC595E4B0F66731C3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_DEEEB64ECE25CDF49573E4B0F665538E" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_EAD69F4258CC8C7CC595E4B0F66731C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAbstract" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_D707E0B2C9DC23AAC77DE4B0F667F950" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_DEEEB64ECE25CDF49573E4B0F665538E" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_D707E0B2C9DC23AAC77DE4B0F667F950" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/CondensedConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_E00F3BF307D35137A29FBB42BF36BCEF" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_37FB1AD7C8DF5226B8339CB44EBD9BB5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_E00F3BF307D35137A29FBB42BF36BCEF" xlink:to="loc_us-gaap_StatementTable_37FB1AD7C8DF5226B8339CB44EBD9BB5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_056164A633B95027B36934DC7A1F7828" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_37FB1AD7C8DF5226B8339CB44EBD9BB5" xlink:to="loc_dei_LegalEntityAxis_056164A633B95027B36934DC7A1F7828" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_5A0C3DD8F99ECE890980A913ED345D99_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_056164A633B95027B36934DC7A1F7828" xlink:to="loc_dei_EntityDomain_5A0C3DD8F99ECE890980A913ED345D99_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_E37BC2CFB8A150A8BE0794ADA9106483" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_056164A633B95027B36934DC7A1F7828" xlink:to="loc_dei_EntityDomain_E37BC2CFB8A150A8BE0794ADA9106483" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_5CC594BDBDBB5683A70B5E9A4B0990CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_E37BC2CFB8A150A8BE0794ADA9106483" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_5CC594BDBDBB5683A70B5E9A4B0990CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_C5FF2E3743075A8F811BB87014433DD2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_E00F3BF307D35137A29FBB42BF36BCEF" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_C5FF2E3743075A8F811BB87014433DD2" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/CondensedConsolidatedStatementsOfOperations" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_CF585198849B988699610321CDC855D0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_StatementTable_CF585198849B988699610321CDC855D0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_3112A4706CB9C784E3140321CDC839E0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_CF585198849B988699610321CDC855D0" xlink:to="loc_dei_LegalEntityAxis_3112A4706CB9C784E3140321CDC839E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_8BC3083F2A70947D1BF10321CDC8BBB2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_3112A4706CB9C784E3140321CDC839E0" xlink:to="loc_dei_EntityDomain_8BC3083F2A70947D1BF10321CDC8BBB2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_8BC3083F2A70947D1BF10321CDC8BBB2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_3112A4706CB9C784E3140321CDC839E0" xlink:to="loc_dei_EntityDomain_8BC3083F2A70947D1BF10321CDC8BBB2" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_EE2BECD37AA2FE195F050321CDC8C4E9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_8BC3083F2A70947D1BF10321CDC8BBB2" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_EE2BECD37AA2FE195F050321CDC8C4E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenuesAbstract" xlink:label="loc_us-gaap_RevenuesAbstract_4B3F24386604908A9CAC0321CDC80FEF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_RevenuesAbstract_4B3F24386604908A9CAC0321CDC80FEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="loc_us-gaap_SalesRevenueGoodsNet_933CF2387DF403058A680321CDC84BAC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_4B3F24386604908A9CAC0321CDC80FEF" xlink:to="loc_us-gaap_SalesRevenueGoodsNet_933CF2387DF403058A680321CDC84BAC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherSalesRevenueNet" xlink:label="loc_us-gaap_OtherSalesRevenueNet_CDB79D41FEA5CABDC35B0321CDC86E83" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_4B3F24386604908A9CAC0321CDC80FEF" xlink:to="loc_us-gaap_OtherSalesRevenueNet_CDB79D41FEA5CABDC35B0321CDC86E83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainLossOnInvestmentsExcludingOtherThanTemporaryImpairments" xlink:label="loc_us-gaap_GainLossOnInvestmentsExcludingOtherThanTemporaryImpairments_BFC8595046887D45143F0321CDC8AC67" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_4B3F24386604908A9CAC0321CDC80FEF" xlink:to="loc_us-gaap_GainLossOnInvestmentsExcludingOtherThanTemporaryImpairments_BFC8595046887D45143F0321CDC8AC67" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestAndDividendIncomeOperating" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperating_74DD1974FB5D387872040321CDC85B00" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_4B3F24386604908A9CAC0321CDC80FEF" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperating_74DD1974FB5D387872040321CDC85B00" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_52359FC23A81D22003DE0321CDC8872C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_4B3F24386604908A9CAC0321CDC80FEF" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_52359FC23A81D22003DE0321CDC8872C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_834733F260AB963763E70321CDC88905" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_4B3F24386604908A9CAC0321CDC80FEF" xlink:to="loc_us-gaap_Revenues_834733F260AB963763E70321CDC88905" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpensesAbstract" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_2638FDA8821662E6083E0321CDC8F03D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_2638FDA8821662E6083E0321CDC8F03D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_7DD7A20370F55DF760D20321CDC8598F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_2638FDA8821662E6083E0321CDC8F03D" xlink:to="loc_us-gaap_CostOfGoodsSold_7DD7A20370F55DF760D20321CDC8598F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherCostAndExpenseOperating" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating_8B61244CC5B293CA8BEB0321CDC8DC29" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_2638FDA8821662E6083E0321CDC8F03D" xlink:to="loc_us-gaap_OtherCostAndExpenseOperating_8B61244CC5B293CA8BEB0321CDC8DC29" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_810288C6DB4AB00A01610321CDC8B01B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_2638FDA8821662E6083E0321CDC8F03D" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_810288C6DB4AB00A01610321CDC8B01B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_4C7369E13EDDEF4226770321CDC8386A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_2638FDA8821662E6083E0321CDC8F03D" xlink:to="loc_us-gaap_RestructuringCharges_4C7369E13EDDEF4226770321CDC8386A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetImpairmentCharges" xlink:label="loc_us-gaap_AssetImpairmentCharges_D14864B2BFF449C644B40321CDC8AB82" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_2638FDA8821662E6083E0321CDC8F03D" xlink:to="loc_us-gaap_AssetImpairmentCharges_D14864B2BFF449C644B40321CDC8AB82" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_4EF8A4402A6E7D5CF6A30321CDC8912F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_2638FDA8821662E6083E0321CDC8F03D" xlink:to="loc_us-gaap_InterestExpense_4EF8A4402A6E7D5CF6A30321CDC8912F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="loc_us-gaap_CostsAndExpenses_51C4963BF0A26E94DCC20321CDD71154" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_2638FDA8821662E6083E0321CDC8F03D" xlink:to="loc_us-gaap_CostsAndExpenses_51C4963BF0A26E94DCC20321CDD71154" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_62F64942B93509FD47E60321CDD7F693" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_62F64942B93509FD47E60321CDD7F693" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_1D4CE824B549B39E79610321CDD7B673" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_1D4CE824B549B39E79610321CDD7B673" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_CD15B420D516BB7143B20321CDD706CB" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_ProfitLoss_CD15B420D516BB7143B20321CDD706CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_497C0B3C72454461C2800321CDD79C12" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_497C0B3C72454461C2800321CDD79C12" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_39513152B17F4BB3D91E0321CDD7701B" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_NetIncomeLoss_39513152B17F4BB3D91E0321CDD7701B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossAbstract" xlink:label="loc_us-gaap_NetIncomeLossAbstract_BC47376BDD047F466EF60321CDD786CF" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_NetIncomeLossAbstract_BC47376BDD047F466EF60321CDD786CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossAllocatedToLimitedPartners" xlink:label="loc_us-gaap_NetIncomeLossAllocatedToLimitedPartners_C395907EFE54C2F65E3A0321CDD7747F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_BC47376BDD047F466EF60321CDD786CF" xlink:to="loc_us-gaap_NetIncomeLossAllocatedToLimitedPartners_C395907EFE54C2F65E3A0321CDD7747F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossAllocatedToGeneralPartners" xlink:label="loc_us-gaap_NetIncomeLossAllocatedToGeneralPartners_203FBD7EFE3104DABAA50321CDD7BD43" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_BC47376BDD047F466EF60321CDD786CF" xlink:to="loc_us-gaap_NetIncomeLossAllocatedToGeneralPartners_203FBD7EFE3104DABAA50321CDD7BD43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerLimitedPartnershipUnitAbstract" xlink:label="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_8B053BBD5820316076790321CDD75DC1" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_8B053BBD5820316076790321CDD75DC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_C7CC4264099B53CD20470321CDD7F219" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_8B053BBD5820316076790321CDD75DC1" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_C7CC4264099B53CD20470321CDD7F219" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding_C49BBC884BA57AA827E30321CDD7F1B1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerLimitedPartnershipUnitAbstract_8B053BBD5820316076790321CDD75DC1" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding_C49BBC884BA57AA827E30321CDD7F1B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareDilutedAbstract" xlink:label="loc_us-gaap_EarningsPerShareDilutedAbstract_BD16B0790A79DA969C910321CDD721A5" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_EarningsPerShareDilutedAbstract_BD16B0790A79DA969C910321CDD721A5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted" xlink:label="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_CD1F152B8E9A1DCFF65E0321CDD78D87" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_BD16B0790A79DA969C910321CDD721A5" xlink:to="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_CD1F152B8E9A1DCFF65E0321CDD78D87" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted_E4A2A7D00E08300330570321CDD70C4A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_BD16B0790A79DA969C910321CDD721A5" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted_E4A2A7D00E08300330570321CDD70C4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DistributionsPerLimitedPartnershipUnitOutstanding" xlink:label="loc_us-gaap_DistributionsPerLimitedPartnershipUnitOutstanding_AE0E71F03732491BC36E0321CDD7E60B" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F7D62140C06E6FD422E00321CDC82C13" xlink:to="loc_us-gaap_DistributionsPerLimitedPartnershipUnitOutstanding_AE0E71F03732491BC36E0321CDD7E60B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/CondensedStatementOfOperationsByReportingSegmentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_26F6850791B71591D5CE1DE593B1FD35" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_26F6850791B71591D5CE1DE593B1FD35" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_8901F34B22D7FF87F9001DE593B19FD0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_26F6850791B71591D5CE1DE593B1FD35" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_8901F34B22D7FF87F9001DE593B19FD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_8901F34B22D7FF87F9001DE593B19FD0" xlink:to="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_8901F34B22D7FF87F9001DE593B19FD0" xlink:to="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InvestmentSegmentMember" xlink:label="loc_iep_InvestmentSegmentMember_EFD49E80D1B3F9FE815D1DE593B110D5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_InvestmentSegmentMember_EFD49E80D1B3F9FE815D1DE593B110D5" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_F14A4AD945EF7E1A975B1DE593B1B654" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_AutomotiveSegmentMember_F14A4AD945EF7E1A975B1DE593B1B654" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_AE0C1513D00ED1A25F211DE593B25AD3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_EnergySegmentMember_AE0C1513D00ED1A25F211DE593B25AD3" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RailcarSegmentMember" xlink:label="loc_iep_RailcarSegmentMember_335B7CD035550DFCE3E11DE593B27D5E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_RailcarSegmentMember_335B7CD035550DFCE3E11DE593B27D5E" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_GamingSegmentMember" xlink:label="loc_iep_GamingSegmentMember_665BC767F33069099A131DE593B2E837" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_GamingSegmentMember_665BC767F33069099A131DE593B2E837" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MetalsSegmentMember" xlink:label="loc_iep_MetalsSegmentMember_53FA2FF2D4F0B93AABAF1DE593B22F15" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_MetalsSegmentMember_53FA2FF2D4F0B93AABAF1DE593B22F15" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MiningsegmentMember" xlink:label="loc_iep_MiningsegmentMember_518B0071A287A2F627911DE593B3A8A9" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_MiningsegmentMember_518B0071A287A2F627911DE593B3A8A9" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FoodPackagingSegmentMember" xlink:label="loc_iep_FoodPackagingSegmentMember_B1E24B63565DC20691E91DE593B301BD" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_FoodPackagingSegmentMember_B1E24B63565DC20691E91DE593B301BD" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RealEstateSegmentMember" xlink:label="loc_iep_RealEstateSegmentMember_4A2C2C5C4CE09FA3AE821DE593B3466D" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_RealEstateSegmentMember_4A2C2C5C4CE09FA3AE821DE593B3466D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_HomeFashionSegmentMember" xlink:label="loc_iep_HomeFashionSegmentMember_B080712F1E1B1EFDCD6A1DE593B3B16B" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_HomeFashionSegmentMember_B080712F1E1B1EFDCD6A1DE593B3B16B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_HoldingCompanyMember" xlink:label="loc_iep_HoldingCompanyMember_1B5D827F5AF86F5A1B881DE593B41AE0" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F08E6FC2F7A40F4F927F1DE593B1C09C" xlink:to="loc_iep_HoldingCompanyMember_1B5D827F5AF86F5A1B881DE593B41AE0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenuesAbstract" xlink:label="loc_us-gaap_RevenuesAbstract_9524BE42EDA0DAF6DA641DE593B47DE8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_RevenuesAbstract_9524BE42EDA0DAF6DA641DE593B47DE8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="loc_us-gaap_SalesRevenueGoodsNet_767396A3CC91B1137BD41DE593B48A66" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_9524BE42EDA0DAF6DA641DE593B47DE8" xlink:to="loc_us-gaap_SalesRevenueGoodsNet_767396A3CC91B1137BD41DE593B48A66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherSalesRevenueNet" xlink:label="loc_us-gaap_OtherSalesRevenueNet_0102A46477CEC9D1BFBB1DE593B426B4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_9524BE42EDA0DAF6DA641DE593B47DE8" xlink:to="loc_us-gaap_OtherSalesRevenueNet_0102A46477CEC9D1BFBB1DE593B426B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainLossOnInvestmentsExcludingOtherThanTemporaryImpairments" xlink:label="loc_us-gaap_GainLossOnInvestmentsExcludingOtherThanTemporaryImpairments_D4D84CF3C2B4CEDAA0E31DE593B4E68E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_9524BE42EDA0DAF6DA641DE593B47DE8" xlink:to="loc_us-gaap_GainLossOnInvestmentsExcludingOtherThanTemporaryImpairments_D4D84CF3C2B4CEDAA0E31DE593B4E68E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestAndDividendIncomeOperating" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperating_DFFD8693F23D868DADB61DE593B4F93B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_9524BE42EDA0DAF6DA641DE593B47DE8" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperating_DFFD8693F23D868DADB61DE593B4F93B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_D76AAFDF61CB444B8C381DE593B4BE5C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_9524BE42EDA0DAF6DA641DE593B47DE8" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_D76AAFDF61CB444B8C381DE593B4BE5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_F5890690A5ADA048446A1DE593B5575B" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_9524BE42EDA0DAF6DA641DE593B47DE8" xlink:to="loc_us-gaap_Revenues_F5890690A5ADA048446A1DE593B5575B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpensesAbstract" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_E91D9AB49D45D41F5D7A1DE593B594DB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_E91D9AB49D45D41F5D7A1DE593B594DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_582B6A453BFBA0916EFC1DE593B50B5C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_E91D9AB49D45D41F5D7A1DE593B594DB" xlink:to="loc_us-gaap_CostOfGoodsSold_582B6A453BFBA0916EFC1DE593B50B5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherCostAndExpenseOperating" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating_F711376E18B7C9FDA9681DE593B5ABF4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_E91D9AB49D45D41F5D7A1DE593B594DB" xlink:to="loc_us-gaap_OtherCostAndExpenseOperating_F711376E18B7C9FDA9681DE593B5ABF4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_D318321F26285959A48B1DE593B5B201" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_E91D9AB49D45D41F5D7A1DE593B594DB" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_D318321F26285959A48B1DE593B5B201" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_F7C365454665D1183FE91DE593B5DC80" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_E91D9AB49D45D41F5D7A1DE593B594DB" xlink:to="loc_us-gaap_RestructuringCharges_F7C365454665D1183FE91DE593B5DC80" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetImpairmentCharges" xlink:label="loc_us-gaap_AssetImpairmentCharges_986F67FE110DD2502EA21DE593B5503A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_E91D9AB49D45D41F5D7A1DE593B594DB" xlink:to="loc_us-gaap_AssetImpairmentCharges_986F67FE110DD2502EA21DE593B5503A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_A723803E861731B09C621DE593B63975" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_E91D9AB49D45D41F5D7A1DE593B594DB" xlink:to="loc_us-gaap_InterestExpense_A723803E861731B09C621DE593B63975" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="loc_us-gaap_CostsAndExpenses_EC59C27DD17FB15F0EE21DE593B64B9F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_E91D9AB49D45D41F5D7A1DE593B594DB" xlink:to="loc_us-gaap_CostsAndExpenses_EC59C27DD17FB15F0EE21DE593B64B9F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_9CB37121BBFBD8CF7E1A1DE593B62293" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_9CB37121BBFBD8CF7E1A1DE593B62293" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_C199B422184B22AAA5AF1DE593B6AE36" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_C199B422184B22AAA5AF1DE593B6AE36" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_98FEE865268463F3E75F1DE593B6D606" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_ProfitLoss_98FEE865268463F3E75F1DE593B6D606" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_0D24F319F0A98DC93B481DE593B643C4" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_0D24F319F0A98DC93B481DE593B643C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_915250B63010FA6579431DE593B6BA5D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_NetIncomeLoss_915250B63010FA6579431DE593B6BA5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SupplementalIncomeStatementElementsAbstract" xlink:label="loc_us-gaap_SupplementalIncomeStatementElementsAbstract_A44581D913C70E8B93AF1DE593B674D1" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_SupplementalIncomeStatementElementsAbstract_A44581D913C70E8B93AF1DE593B674D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_2C4464CDEBE0C4E9261F1DE593B6316E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalIncomeStatementElementsAbstract_A44581D913C70E8B93AF1DE593B674D1" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_2C4464CDEBE0C4E9261F1DE593B6316E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_46E6F36F23895210FF171DE593B7E635" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalIncomeStatementElementsAbstract_A44581D913C70E8B93AF1DE593B674D1" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_46E6F36F23895210FF171DE593B7E635" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:label="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts_516610A21C460C0042CF1DE593B71265" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_5F7FE6C98202CEC847B71DE593B4062A" xlink:to="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts_516610A21C460C0042CF1DE593B71265" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/Debt" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/DebtDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_526E5470A0ADB4E95D271DE593F4FCD5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_3A901C19F0B5F36E2D661DE593F09380" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_526E5470A0ADB4E95D271DE593F4FCD5" xlink:to="loc_us-gaap_DebtInstrumentTable_3A901C19F0B5F36E2D661DE593F09380" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_C9F1CF47182FF79C1A0A1DE593F1A825" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3A901C19F0B5F36E2D661DE593F09380" xlink:to="loc_us-gaap_DebtInstrumentAxis_C9F1CF47182FF79C1A0A1DE593F1A825" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1972CFBD6EE56B4EA24C1DE593F1FFEB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_C9F1CF47182FF79C1A0A1DE593F1A825" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1972CFBD6EE56B4EA24C1DE593F1FFEB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1972CFBD6EE56B4EA24C1DE593F1FFEB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_C9F1CF47182FF79C1A0A1DE593F1A825" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1972CFBD6EE56B4EA24C1DE593F1FFEB" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_A2020NotesMember" xlink:label="loc_iep_A2020NotesMember_7F520BF5EF83DE55A8241DE593F1DE60" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1972CFBD6EE56B4EA24C1DE593F1FFEB" xlink:to="loc_iep_A2020NotesMember_7F520BF5EF83DE55A8241DE593F1DE60" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_A2022NotesMember" xlink:label="loc_iep_A2022NotesMember_8A27958B7D4684615CE01DE593F1D26F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1972CFBD6EE56B4EA24C1DE593F1FFEB" xlink:to="loc_iep_A2022NotesMember_8A27958B7D4684615CE01DE593F1D26F" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_New2022NotesMember" xlink:label="loc_iep_New2022NotesMember_0F632AAFCC8D0E509D4E1DE593F10456" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1972CFBD6EE56B4EA24C1DE593F1FFEB" xlink:to="loc_iep_New2022NotesMember_0F632AAFCC8D0E509D4E1DE593F10456" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_A2024NotesMember" xlink:label="loc_iep_A2024NotesMember_6573BE8F0992F59451961DE593F1A7D7" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1972CFBD6EE56B4EA24C1DE593F1FFEB" xlink:to="loc_iep_A2024NotesMember_6573BE8F0992F59451961DE593F1A7D7" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_A2025NotesMember" xlink:label="loc_iep_A2025NotesMember_104FC275B4F6108BF0F91DE593F1DD7C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1972CFBD6EE56B4EA24C1DE593F1FFEB" xlink:to="loc_iep_A2025NotesMember_104FC275B4F6108BF0F91DE593F1DD7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_B85877C82C8B91D59A761DE593F232A3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3A901C19F0B5F36E2D661DE593F09380" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_B85877C82C8B91D59A761DE593F232A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_B85877C82C8B91D59A761DE593F232A3" xlink:to="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_B85877C82C8B91D59A761DE593F232A3" xlink:to="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ReportingSegmentsMember" xlink:label="loc_iep_ReportingSegmentsMember_35292E6142A37DBCAF151DE593F20C7E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_ReportingSegmentsMember_35292E6142A37DBCAF151DE593F20C7E" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_HoldingCompanyMember" xlink:label="loc_iep_HoldingCompanyMember_D5AECF51C6C9D707F12F1DE593F2503F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_HoldingCompanyMember_D5AECF51C6C9D707F12F1DE593F2503F" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_77C626B3022097B565E01DE593F2E9FB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_AutomotiveSegmentMember_77C626B3022097B565E01DE593F2E9FB" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_6000A7B907E56496A7AF1DE593F2FCC1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_EnergySegmentMember_6000A7B907E56496A7AF1DE593F2FCC1" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RailcarSegmentMember" xlink:label="loc_iep_RailcarSegmentMember_2968D2ED797552AF20751DE593F2AC86" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_RailcarSegmentMember_2968D2ED797552AF20751DE593F2AC86" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_GamingSegmentMember" xlink:label="loc_iep_GamingSegmentMember_CF6136038FB73C3F8CD61DE593F34EA8" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_GamingSegmentMember_CF6136038FB73C3F8CD61DE593F34EA8" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MetalsSegmentMember" xlink:label="loc_iep_MetalsSegmentMember_0C7EC432F783CDA127571DE593F3F51D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_MetalsSegmentMember_0C7EC432F783CDA127571DE593F3F51D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MiningsegmentMember" xlink:label="loc_iep_MiningsegmentMember_0C08A6993E0D3FC064941DE593F448AB" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_MiningsegmentMember_0C08A6993E0D3FC064941DE593F448AB" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FoodPackagingSegmentMember" xlink:label="loc_iep_FoodPackagingSegmentMember_EB536A3D9018018571A61DE593F4DF77" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_FoodPackagingSegmentMember_EB536A3D9018018571A61DE593F4DF77" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RealEstateSegmentMember" xlink:label="loc_iep_RealEstateSegmentMember_DF9C4AFEE5F2F8D8E2B41DE593F49CDB" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_RealEstateSegmentMember_DF9C4AFEE5F2F8D8E2B41DE593F49CDB" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_HomeFashionSegmentMember" xlink:label="loc_iep_HomeFashionSegmentMember_A6FEC94ACAA40EB480FA1DE593F463B8" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_D71C1253A9D44A1357141DE593F2FC3A" xlink:to="loc_iep_HomeFashionSegmentMember_A6FEC94ACAA40EB480FA1DE593F463B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtAndCapitalLeaseObligations" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_BBBB7AAEEF21DC8B6D3E1DE593F478B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_526E5470A0ADB4E95D271DE593F4FCD5" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_BBBB7AAEEF21DC8B6D3E1DE593F478B5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/DebtTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/DescriptionOfBusiness" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/Details" xlink:type="extended">
    <link:loc xlink:href="iep-20180331.xsd#iep_DescriptionofBusinessLineItems" xlink:label="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:type="locator" />
    <link:loc xlink:href="iep-20180331.xsd#iep_DescriptionofBusinessTable" xlink:label="loc_iep_DescriptionofBusinessTable_D8501BA50A87F34B056B26E95D38867F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_iep_DescriptionofBusinessTable_D8501BA50A87F34B056B26E95D38867F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_96ADBCC063EF746A7EF126E95D38D4B1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_DescriptionofBusinessTable_D8501BA50A87F34B056B26E95D38867F" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_96ADBCC063EF746A7EF126E95D38D4B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_84F71BD3F92FC984B0BF26E95D387310_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_96ADBCC063EF746A7EF126E95D38D4B1" xlink:to="loc_us-gaap_SegmentDomain_84F71BD3F92FC984B0BF26E95D387310_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_84F71BD3F92FC984B0BF26E95D387310" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_96ADBCC063EF746A7EF126E95D38D4B1" xlink:to="loc_us-gaap_SegmentDomain_84F71BD3F92FC984B0BF26E95D387310" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_FF3AD1A31E59DB89BF6026E95D38F9F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_84F71BD3F92FC984B0BF26E95D387310" xlink:to="loc_iep_AutomotiveSegmentMember_FF3AD1A31E59DB89BF6026E95D38F9F0" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_EA1DAB809017B13E5C5B26E95D38D849" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_84F71BD3F92FC984B0BF26E95D387310" xlink:to="loc_iep_EnergySegmentMember_EA1DAB809017B13E5C5B26E95D38D849" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FoodPackagingSegmentMember" xlink:label="loc_iep_FoodPackagingSegmentMember_042210B1B542BEBB942C26E95D396960" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_84F71BD3F92FC984B0BF26E95D387310" xlink:to="loc_iep_FoodPackagingSegmentMember_042210B1B542BEBB942C26E95D396960" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MembersOrPartnersAxis" xlink:label="loc_iep_MembersOrPartnersAxis_88BCCDBCD96F7F369CF326E95D39FC1F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_DescriptionofBusinessTable_D8501BA50A87F34B056B26E95D38867F" xlink:to="loc_iep_MembersOrPartnersAxis_88BCCDBCD96F7F369CF326E95D39FC1F" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PartnerNameDomain" xlink:label="loc_iep_PartnerNameDomain_1AC54C6CFA0C3F8D3E0026E95D397381_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_iep_MembersOrPartnersAxis_88BCCDBCD96F7F369CF326E95D39FC1F" xlink:to="loc_iep_PartnerNameDomain_1AC54C6CFA0C3F8D3E0026E95D397381_default" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PartnerNameDomain" xlink:label="loc_iep_PartnerNameDomain_1AC54C6CFA0C3F8D3E0026E95D397381" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_iep_MembersOrPartnersAxis_88BCCDBCD96F7F369CF326E95D39FC1F" xlink:to="loc_iep_PartnerNameDomain_1AC54C6CFA0C3F8D3E0026E95D397381" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesGPMember" xlink:label="loc_iep_IcahnEnterprisesGPMember_A4B40742692621F159BB26E95D399938" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_PartnerNameDomain_1AC54C6CFA0C3F8D3E0026E95D397381" xlink:to="loc_iep_IcahnEnterprisesGPMember_A4B40742692621F159BB26E95D399938" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PrincipalOwnersAndAffiliatesMember" xlink:label="loc_iep_PrincipalOwnersAndAffiliatesMember_13BBC88FBFCF74783CD626E95D39628C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_PartnerNameDomain_1AC54C6CFA0C3F8D3E0026E95D397381" xlink:to="loc_iep_PrincipalOwnersAndAffiliatesMember_13BBC88FBFCF74783CD626E95D39628C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_452D09DA8338CB5D107126E95D3A11FE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_DescriptionofBusinessTable_D8501BA50A87F34B056B26E95D38867F" xlink:to="loc_dei_LegalEntityAxis_452D09DA8338CB5D107126E95D3A11FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_452D09DA8338CB5D107126E95D3A11FE" xlink:to="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_452D09DA8338CB5D107126E95D3A11FE" xlink:to="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_DAC576D9EAE96BF851C626E95D3BCA54" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_DAC576D9EAE96BF851C626E95D3BCA54" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesGPMember" xlink:label="loc_iep_IcahnEnterprisesGPMember_6ACDA013D203A1814C8026E95D3BB63A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_IcahnEnterprisesGPMember_6ACDA013D203A1814C8026E95D3BB63A" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InvestmentFundsMember" xlink:label="loc_iep_InvestmentFundsMember_F352260EB8008D82D3DE26E95D3BF46C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_InvestmentFundsMember_F352260EB8008D82D3DE26E95D3BF46C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FederalMogulMember" xlink:label="loc_iep_FederalMogulMember_460FF6B7D59A0CA1FBAE26E95D3BDCE4" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_FederalMogulMember_460FF6B7D59A0CA1FBAE26E95D3BDCE4" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_CvrRefiningLpMember" xlink:label="loc_iep_CvrRefiningLpMember_C9AFF6A1EAE4A6E26D3E26E95D3B83F1" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_CvrRefiningLpMember_C9AFF6A1EAE4A6E26D3E26E95D3B83F1" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_CvrPartnersLpMember" xlink:label="loc_iep_CvrPartnersLpMember_A4EA211A0A5B49254FE226E95D3BA4BA" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_CvrPartnersLpMember_A4EA211A0A5B49254FE226E95D3BA4BA" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_CvrEnergyIncMember" xlink:label="loc_iep_CvrEnergyIncMember_03DF077890C758A8EA4D26E95D3BCDA5" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_CvrEnergyIncMember_03DF077890C758A8EA4D26E95D3BCDA5" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AriMember" xlink:label="loc_iep_AriMember_B096C249565294FF82DA26E95D3B888A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_AriMember_B096C249565294FF82DA26E95D3B888A" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_TropicanaMember" xlink:label="loc_iep_TropicanaMember_3B72732673021114ED1326E95D3CE64E" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_TropicanaMember_3B72732673021114ED1326E95D3CE64E" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FerrousResourcesMember" xlink:label="loc_iep_FerrousResourcesMember_1C0553D4FADE96621A5526E95D3C4B9D" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_FerrousResourcesMember_1C0553D4FADE96621A5526E95D3C4B9D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ViskaseMember" xlink:label="loc_iep_ViskaseMember_6672A65C4BD7065A4C9326E95D3C52BE" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EE639A37A7479AD3E3FA26E95D3A6396" xlink:to="loc_iep_ViskaseMember_6672A65C4BD7065A4C9326E95D3C52BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest" xlink:label="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_69432CFD541C7A4A5F9426E95D3CC43B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest_69432CFD541C7A4A5F9426E95D3CC43B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ProceedsFromRightsOffering" xlink:label="loc_iep_ProceedsFromRightsOffering_78820A92BDA2160AB11126E95D3C2036" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_iep_ProceedsFromRightsOffering_78820A92BDA2160AB11126E95D3C2036" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries" xlink:label="loc_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries_83D6C9B18926D9026E3226E95D3CEF7E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries_83D6C9B18926D9026E3226E95D3CEF7E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_33E4D818C3D8EBC9138726E95D3CB1C9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_33E4D818C3D8EBC9138726E95D3CB1C9" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_SubsidiaryOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterest" xlink:label="loc_iep_SubsidiaryOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterest_D9C721370A02F90907E126E95D3CD7B7" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_iep_SubsidiaryOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterest_D9C721370A02F90907E126E95D3CD7B7" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_LimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerAggregateOwnershipInterestOfParentAndHoldingCompanySubsidiaries" xlink:label="loc_iep_LimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerAggregateOwnershipInterestOfParentAndHoldingCompanySubsidiaries_84313E3CAB8CDF13F43826E95D3DBF6A" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_iep_LimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerAggregateOwnershipInterestOfParentAndHoldingCompanySubsidiaries_84313E3CAB8CDF13F43826E95D3DBF6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_0430C894C0710CF3FAF726E95D3D043D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_0430C894C0710CF3FAF726E95D3D043D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterestFairValue" xlink:label="loc_iep_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterestFairValue_4CF5D2A5846467F0094E26E95D3DECE9" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_iep_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterestFairValue_4CF5D2A5846467F0094E26E95D3DECE9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates" xlink:label="loc_us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates_15035DA161A31C8E74EF26E95D3DCDA5" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DescriptionofBusinessLineItems_E8A183DE4E33D073EC3B26E95D3CE7DA" xlink:to="loc_us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates_15035DA161A31C8E74EF26E95D3DCDA5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/DocumentAndEntityInformationDocument" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityInformationLineItems" xlink:label="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntitiesTable" xlink:label="loc_dei_EntitiesTable_40D364CA1A6E569BACE6AEB3FE48F9AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_EntitiesTable_40D364CA1A6E569BACE6AEB3FE48F9AE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_8BC2FD182BAD5E3791A9C5084A1F50DD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_40D364CA1A6E569BACE6AEB3FE48F9AE" xlink:to="loc_dei_LegalEntityAxis_8BC2FD182BAD5E3791A9C5084A1F50DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_3436C3D3F2D1B5813383A913ED666C68_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_8BC2FD182BAD5E3791A9C5084A1F50DD" xlink:to="loc_dei_EntityDomain_3436C3D3F2D1B5813383A913ED666C68_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_0993F0DABD2F50DEBD77203D0497AB93" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_8BC2FD182BAD5E3791A9C5084A1F50DD" xlink:to="loc_dei_EntityDomain_0993F0DABD2F50DEBD77203D0497AB93" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnEnterprisesHoldingsMember" xlink:label="loc_iep_IcahnEnterprisesHoldingsMember_53FFC8FD2386546F953B193CBAC51113" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_0993F0DABD2F50DEBD77203D0497AB93" xlink:to="loc_iep_IcahnEnterprisesHoldingsMember_53FFC8FD2386546F953B193CBAC51113" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_2F5896E834E35FC4BAA31AAEF4DBE605" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_EntityRegistrantName_2F5896E834E35FC4BAA31AAEF4DBE605" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_TradingSymbol" xlink:label="loc_dei_TradingSymbol_AF6F4377E6B058B4BEB09C98D65697EC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_TradingSymbol_AF6F4377E6B058B4BEB09C98D65697EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_45375BBD580A5ECAA2979BD50DA04553" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_EntityCentralIndexKey_45375BBD580A5ECAA2979BD50DA04553" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate_8AD91B070C5E5216BE79DC9F7E98B65C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_CurrentFiscalYearEndDate_8AD91B070C5E5216BE79DC9F7E98B65C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityFilerCategory" xlink:label="loc_dei_EntityFilerCategory_10C584350FCB5A089619E4A651472000" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_EntityFilerCategory_10C584350FCB5A089619E4A651472000" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_FC92F37D3AB75D6B884598BB082D1E18" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_DocumentType_FC92F37D3AB75D6B884598BB082D1E18" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_E93B5A783E6B5D7CBFAD1AE891E6E927" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_DocumentPeriodEndDate_E93B5A783E6B5D7CBFAD1AE891E6E927" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus_804F251F928A592FAB3D832E980F8255" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_DocumentFiscalYearFocus_804F251F928A592FAB3D832E980F8255" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus_6F907A8EDD6F50ABAF2974AB4EF44B96" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_DocumentFiscalPeriodFocus_6F907A8EDD6F50ABAF2974AB4EF44B96" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_55068A49E2C45130B2DBE44A501A4BCB" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_AmendmentFlag_55068A49E2C45130B2DBE44A501A4BCB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_17B857D8A0275B0A9FFD9E107E68A866" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_17B857D8A0275B0A9FFD9E107E68A866" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityWellKnownSeasonedIssuer" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_D002D925BB1C5A64A268286832CE061E" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_D002D925BB1C5A64A268286832CE061E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCurrentReportingStatus" xlink:label="loc_dei_EntityCurrentReportingStatus_C859B405C195575998A242EA77BCDECB" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_C1506D4AB33F5067B94EBC95D5C59304" xlink:to="loc_dei_EntityCurrentReportingStatus_C859B405C195575998A242EA77BCDECB" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/FairValueMeasurements" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/FairValueMeasurementsChangesInFairValueLevel3Details" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_13E211E5C798FECFC6FCE4B84D499593" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_40670430C09FC8DE13D6E4B84D48EEBD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_13E211E5C798FECFC6FCE4B84D499593" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_40670430C09FC8DE13D6E4B84D48EEBD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_94213FD0998F3AC9E0B3E4B84D486317" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_40670430C09FC8DE13D6E4B84D48EEBD" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_94213FD0998F3AC9E0B3E4B84D486317" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_2001EBF0A7009A61D4C0E4B84D482353_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_94213FD0998F3AC9E0B3E4B84D486317" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_2001EBF0A7009A61D4C0E4B84D482353_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_2001EBF0A7009A61D4C0E4B84D482353" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_94213FD0998F3AC9E0B3E4B84D486317" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_2001EBF0A7009A61D4C0E4B84D482353" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_9E9DED2E7EE3B803A781E4B84D48B50D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_2001EBF0A7009A61D4C0E4B84D482353" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_9E9DED2E7EE3B803A781E4B84D48B50D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_262051B68D07BE919A9FE4B84D48F69F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_40670430C09FC8DE13D6E4B84D48EEBD" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_262051B68D07BE919A9FE4B84D48F69F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B2269C22907E655FD0EBE4B84D49508A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_262051B68D07BE919A9FE4B84D48F69F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B2269C22907E655FD0EBE4B84D49508A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B2269C22907E655FD0EBE4B84D49508A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_262051B68D07BE919A9FE4B84D48F69F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B2269C22907E655FD0EBE4B84D49508A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_CFCAE610C5F73364658AE4B84D49DCD2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_B2269C22907E655FD0EBE4B84D49508A" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_CFCAE610C5F73364658AE4B84D49DCD2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E5250995A2A3CB47F616E4B84D499A07" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_13E211E5C798FECFC6FCE4B84D499593" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E5250995A2A3CB47F616E4B84D499A07" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_4B9CDA6D49C106A5DBD6E4B84D490E06" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E5250995A2A3CB47F616E4B84D499A07" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_4B9CDA6D49C106A5DBD6E4B84D490E06" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Fairvaluemeasurementwithunobservableinputsreconciliationrecurringbasisassetsunrealizedgainloss" xlink:label="loc_iep_Fairvaluemeasurementwithunobservableinputsreconciliationrecurringbasisassetsunrealizedgainloss_72C3D21340AD9532671EE4B84D49524A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E5250995A2A3CB47F616E4B84D499A07" xlink:to="loc_iep_Fairvaluemeasurementwithunobservableinputsreconciliationrecurringbasisassetsunrealizedgainloss_72C3D21340AD9532671EE4B84D49524A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3_C4F9CC8EB533AB70AB07E4B84D4BC68C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_E5250995A2A3CB47F616E4B84D499A07" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3_C4F9CC8EB533AB70AB07E4B84D4BC68C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/FairValueMeasurementsFairValueMeasurementDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_DB3F1AC1408352208E145B46B355EE6E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8A87996D97765EF6BA0CDAD8604885AA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_DB3F1AC1408352208E145B46B355EE6E" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8A87996D97765EF6BA0CDAD8604885AA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_67E5C332F91F5829909BC0D1DE4B902F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8A87996D97765EF6BA0CDAD8604885AA" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_67E5C332F91F5829909BC0D1DE4B902F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_585500DD047BE0B435EAA913EC208078_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_67E5C332F91F5829909BC0D1DE4B902F" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_585500DD047BE0B435EAA913EC208078_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_2DB42E0E1DCC58018942AA175123928C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_67E5C332F91F5829909BC0D1DE4B902F" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_2DB42E0E1DCC58018942AA175123928C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_0856445545E253F190454D54D5996822" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_2DB42E0E1DCC58018942AA175123928C" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_0856445545E253F190454D54D5996822" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A33ABF4377685DED82658786CA0F12FC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8A87996D97765EF6BA0CDAD8604885AA" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A33ABF4377685DED82658786CA0F12FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_8C085EF0B8916B005AC1A913EC2043B3_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A33ABF4377685DED82658786CA0F12FC" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_8C085EF0B8916B005AC1A913EC2043B3_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_34FA44480B0F5220B1B8736A5D51DF5F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_A33ABF4377685DED82658786CA0F12FC" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_34FA44480B0F5220B1B8736A5D51DF5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_67D1BC7DC94658358BA96C9D9CD96E8A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_34FA44480B0F5220B1B8736A5D51DF5F" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_67D1BC7DC94658358BA96C9D9CD96E8A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_3732E4D4371D54499DA5AB07478BAD03" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_34FA44480B0F5220B1B8736A5D51DF5F" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_3732E4D4371D54499DA5AB07478BAD03" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_65917B91B9CD50B99BC559E2896DA9D1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_34FA44480B0F5220B1B8736A5D51DF5F" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_65917B91B9CD50B99BC559E2896DA9D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_0B3C830985A857CCAC0E2552769537F2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_DB3F1AC1408352208E145B46B355EE6E" xlink:to="loc_us-gaap_AssetsAbstract_0B3C830985A857CCAC0E2552769537F2" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Investmentsmeasuredatfairvalue" xlink:label="loc_iep_Investmentsmeasuredatfairvalue_8A5A04C5D0EF54EEAF9F2648BF4FBE52" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_0B3C830985A857CCAC0E2552769537F2" xlink:to="loc_iep_Investmentsmeasuredatfairvalue_8A5A04C5D0EF54EEAF9F2648BF4FBE52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssets" xlink:label="loc_us-gaap_DerivativeAssets_4EBC618218A9584D9F342DD67728A0EC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_0B3C830985A857CCAC0E2552769537F2" xlink:to="loc_us-gaap_DerivativeAssets_4EBC618218A9584D9F342DD67728A0EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_46BF065D978C5B67876759B1F6A166BF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_0B3C830985A857CCAC0E2552769537F2" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_46BF065D978C5B67876759B1F6A166BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAbstract" xlink:label="loc_us-gaap_LiabilitiesAbstract_1432E90003815E4EB447546ADFE1C906" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_DB3F1AC1408352208E145B46B355EE6E" xlink:to="loc_us-gaap_LiabilitiesAbstract_1432E90003815E4EB447546ADFE1C906" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue" xlink:label="loc_us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue_05257F826C5B5B81859947AEDD073AD8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_1432E90003815E4EB447546ADFE1C906" xlink:to="loc_us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue_05257F826C5B5B81859947AEDD073AD8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesFairValueDisclosure" xlink:label="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_A8EC2F4F0F3B5EDCA19D4A96D906B043" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_1432E90003815E4EB447546ADFE1C906" xlink:to="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_A8EC2F4F0F3B5EDCA19D4A96D906B043" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaap_DerivativeLiabilities_F5825903A24255B4A3A54D4FC41E3609" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_1432E90003815E4EB447546ADFE1C906" xlink:to="loc_us-gaap_DerivativeLiabilities_F5825903A24255B4A3A54D4FC41E3609" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_33FEEF7AB65F5E4C8A6B318A5F44F68E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_1432E90003815E4EB447546ADFE1C906" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_33FEEF7AB65F5E4C8A6B318A5F44F68E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInstrumentsClassifiedInShareholdersEquityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:label="loc_us-gaap_FairValueInstrumentsClassifiedInShareholdersEquityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_E205914ECC381048C5C4FD89ADEB1D93" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_AFF16CCDA42B63876899FD89ADE9E0A1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueInstrumentsClassifiedInShareholdersEquityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_E205914ECC381048C5C4FD89ADEB1D93" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_AFF16CCDA42B63876899FD89ADE9E0A1" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_98D2992A5FA1A2E752CEFD89ADEB2041" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_AFF16CCDA42B63876899FD89ADE9E0A1" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_98D2992A5FA1A2E752CEFD89ADEB2041" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_C6E6C2EB1DBB18147634FD89ADEBDA0C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_98D2992A5FA1A2E752CEFD89ADEB2041" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_C6E6C2EB1DBB18147634FD89ADEBDA0C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_C6E6C2EB1DBB18147634FD89ADEBDA0C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_98D2992A5FA1A2E752CEFD89ADEB2041" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_C6E6C2EB1DBB18147634FD89ADEBDA0C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_7C3D7AEF45A71E477870FD89ADEB8270" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_C6E6C2EB1DBB18147634FD89ADEBDA0C" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_7C3D7AEF45A71E477870FD89ADEB8270" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_967451E8AB7E37ACD217FD89ADEB4F0B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_C6E6C2EB1DBB18147634FD89ADEBDA0C" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_967451E8AB7E37ACD217FD89ADEB4F0B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_6307311C606BEE577CC7FD89ADEB5540" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_AFF16CCDA42B63876899FD89ADE9E0A1" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_6307311C606BEE577CC7FD89ADEB5540" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_1599354CD5404B0D42DEFD89ADEBBF16_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_6307311C606BEE577CC7FD89ADEB5540" xlink:to="loc_us-gaap_SegmentDomain_1599354CD5404B0D42DEFD89ADEBBF16_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_1599354CD5404B0D42DEFD89ADEBBF16" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_6307311C606BEE577CC7FD89ADEB5540" xlink:to="loc_us-gaap_SegmentDomain_1599354CD5404B0D42DEFD89ADEBBF16" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_HoldingCompanyMember" xlink:label="loc_iep_HoldingCompanyMember_62508329842B31DF81AFFD89ADEBDBE8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_1599354CD5404B0D42DEFD89ADEBBF16" xlink:to="loc_iep_HoldingCompanyMember_62508329842B31DF81AFFD89ADEBDBE8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="loc_us-gaap_InvestmentTypeAxis_D52E8B4FCF2532A48B71FD89ADEBF97E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_AFF16CCDA42B63876899FD89ADE9E0A1" xlink:to="loc_us-gaap_InvestmentTypeAxis_D52E8B4FCF2532A48B71FD89ADEBF97E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_3D0D747DEDD85986ACF5FD89ADEB2B91_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_D52E8B4FCF2532A48B71FD89ADEBF97E" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_3D0D747DEDD85986ACF5FD89ADEB2B91_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_3D0D747DEDD85986ACF5FD89ADEB2B91" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_D52E8B4FCF2532A48B71FD89ADEBF97E" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_3D0D747DEDD85986ACF5FD89ADEB2B91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TradingAccountAssetsMember" xlink:label="loc_us-gaap_TradingAccountAssetsMember_6558E5040FDD30CF0521FD89ADEBE521" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_3D0D747DEDD85986ACF5FD89ADEB2B91" xlink:to="loc_us-gaap_TradingAccountAssetsMember_6558E5040FDD30CF0521FD89ADEBE521" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_48E4ED3FE6A4F42830D2FD89ADEB3B92" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_AFF16CCDA42B63876899FD89ADE9E0A1" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_48E4ED3FE6A4F42830D2FD89ADEB3B92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6C3B2A9F45D8AD4FE57BFD89ADEB6F00_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_48E4ED3FE6A4F42830D2FD89ADEB3B92" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6C3B2A9F45D8AD4FE57BFD89ADEB6F00_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6C3B2A9F45D8AD4FE57BFD89ADEB6F00" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_48E4ED3FE6A4F42830D2FD89ADEB3B92" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6C3B2A9F45D8AD4FE57BFD89ADEB6F00" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_FA0B22CB30BE688C84F0FD89ADEB3DF8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6C3B2A9F45D8AD4FE57BFD89ADEB6F00" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_FA0B22CB30BE688C84F0FD89ADEB3DF8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_9DE40A9EF6ED029A732CFD89ADEB196F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueInstrumentsClassifiedInShareholdersEquityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_E205914ECC381048C5C4FD89ADEB1D93" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_9DE40A9EF6ED029A732CFD89ADEB196F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ImpairmentOfLongLivedAssetsHeldForUse" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_7C57FC0789D7111A14F0FD89ADEBD223" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueInstrumentsClassifiedInShareholdersEquityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_E205914ECC381048C5C4FD89ADEB1D93" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_7C57FC0789D7111A14F0FD89ADEBD223" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryWriteDown" xlink:label="loc_us-gaap_InventoryWriteDown_37164E12754E0C2EA95FFD89ADEB7563" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueInstrumentsClassifiedInShareholdersEquityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_E205914ECC381048C5C4FD89ADEB1D93" xlink:to="loc_us-gaap_InventoryWriteDown_37164E12754E0C2EA95FFD89ADEB7563" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetImpairmentCharges" xlink:label="loc_us-gaap_AssetImpairmentCharges_59C07728337A8EFD2ECDFD89C7F0E941" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueInstrumentsClassifiedInShareholdersEquityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_E205914ECC381048C5C4FD89ADEB1D93" xlink:to="loc_us-gaap_AssetImpairmentCharges_59C07728337A8EFD2ECDFD89C7F0E941" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/FairValueMeasurementsPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/FairValueMeasurementsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/FinancialInstruments" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/FinancialInstrumentsDerivativeActivitiesTableDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_EECA1344349361B1FE81DFD991A9256B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_9F2E8B8CD8A413BA8B69DFD991A9DBD7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_EECA1344349361B1FE81DFD991A9256B" xlink:to="loc_us-gaap_DerivativeTable_9F2E8B8CD8A413BA8B69DFD991A9DBD7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_0E171612EA8D965D4A21DFD991A9B8D8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9F2E8B8CD8A413BA8B69DFD991A9DBD7" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_0E171612EA8D965D4A21DFD991A9B8D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_CCDE901DE91805E49056DFD991A94FC6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_0E171612EA8D965D4A21DFD991A9B8D8" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_CCDE901DE91805E49056DFD991A94FC6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_CCDE901DE91805E49056DFD991A94FC6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_0E171612EA8D965D4A21DFD991A9B8D8" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_CCDE901DE91805E49056DFD991A94FC6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityContractMember" xlink:label="loc_us-gaap_EquityContractMember_F29E3A2585178A240D9ADFD991A974FB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_CCDE901DE91805E49056DFD991A94FC6" xlink:to="loc_us-gaap_EquityContractMember_F29E3A2585178A240D9ADFD991A974FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditRiskContractMember" xlink:label="loc_us-gaap_CreditRiskContractMember_FF071BDF4D2678B6DDBCDFD991A965BB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_CCDE901DE91805E49056DFD991A94FC6" xlink:to="loc_us-gaap_CreditRiskContractMember_FF071BDF4D2678B6DDBCDFD991A965BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommodityContractMember" xlink:label="loc_us-gaap_CommodityContractMember_AB5FA172D7E9A29159E6DFD991A9E8BD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_CCDE901DE91805E49056DFD991A94FC6" xlink:to="loc_us-gaap_CommodityContractMember_AB5FA172D7E9A29159E6DFD991A9E8BD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditDefaultSwapMember" xlink:label="loc_us-gaap_CreditDefaultSwapMember_A842233A1C462E382D5BDFD991A9A10E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_CCDE901DE91805E49056DFD991A94FC6" xlink:to="loc_us-gaap_CreditDefaultSwapMember_A842233A1C462E382D5BDFD991A9A10E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmountVolume" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_7FEABA3E3A088B78ABEADFD991A9C924" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_EECA1344349361B1FE81DFD991A9256B" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_7FEABA3E3A088B78ABEADFD991A9C924" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_NotionalExposureOfDerivativesLongPosition" xlink:label="loc_iep_NotionalExposureOfDerivativesLongPosition_BE9AAAF13DB9FF31DDCFDFD991A98FFB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_EECA1344349361B1FE81DFD991A9256B" xlink:to="loc_iep_NotionalExposureOfDerivativesLongPosition_BE9AAAF13DB9FF31DDCFDFD991A98FFB" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_NotionalExposureOfDerivativesShortPosition" xlink:label="loc_iep_NotionalExposureOfDerivativesShortPosition_988C2E482BC86E55EA12DFD991A9320D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_EECA1344349361B1FE81DFD991A9256B" xlink:to="loc_iep_NotionalExposureOfDerivativesShortPosition_988C2E482BC86E55EA12DFD991A9320D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_DerivativeNotionalAmount" xlink:label="loc_invest_DerivativeNotionalAmount_D22368AF75E12D240BD0DFD991A9B269" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_EECA1344349361B1FE81DFD991A9256B" xlink:to="loc_invest_DerivativeNotionalAmount_D22368AF75E12D240BD0DFD991A9B269" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/FinancialInstrumentsDerivativesNotDesignatedAsHedgingFairValueTableDetails" xlink:type="extended">
    <link:loc xlink:href="iep-20180331.xsd#iep_DerivativesNotDesignatedAsHedgingInstrumentsFairValueLineItems" xlink:label="loc_iep_DerivativesNotDesignatedAsHedgingInstrumentsFairValueLineItems_ACE909176B0E5E6A637DE4B91EA6015E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_32CC3EC7995AEA2E5ED5E4B91EA3C68F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_iep_DerivativesNotDesignatedAsHedgingInstrumentsFairValueLineItems_ACE909176B0E5E6A637DE4B91EA6015E" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_32CC3EC7995AEA2E5ED5E4B91EA3C68F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_BF0DDD415F038DE43CF7E4B91EA31E39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_32CC3EC7995AEA2E5ED5E4B91EA3C68F" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_BF0DDD415F038DE43CF7E4B91EA31E39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_921D981FACD334D8F30BE4B91EA38AAA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_BF0DDD415F038DE43CF7E4B91EA31E39" xlink:to="loc_us-gaap_SegmentDomain_921D981FACD334D8F30BE4B91EA38AAA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_921D981FACD334D8F30BE4B91EA38AAA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_BF0DDD415F038DE43CF7E4B91EA31E39" xlink:to="loc_us-gaap_SegmentDomain_921D981FACD334D8F30BE4B91EA38AAA" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InvestmentSegmentMember" xlink:label="loc_iep_InvestmentSegmentMember_1D997E641E15259AEAE5E4B91EA3C699" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_921D981FACD334D8F30BE4B91EA38AAA" xlink:to="loc_iep_InvestmentSegmentMember_1D997E641E15259AEAE5E4B91EA3C699" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_C2D5C2BE38691213BEB5E4B91EA38115" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_32CC3EC7995AEA2E5ED5E4B91EA3C68F" xlink:to="loc_us-gaap_HedgingDesignationAxis_C2D5C2BE38691213BEB5E4B91EA38115" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_B8933DB69A1F82C088ABE4B91EA5777F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_C2D5C2BE38691213BEB5E4B91EA38115" xlink:to="loc_us-gaap_HedgingDesignationDomain_B8933DB69A1F82C088ABE4B91EA5777F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_B8933DB69A1F82C088ABE4B91EA5777F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_C2D5C2BE38691213BEB5E4B91EA38115" xlink:to="loc_us-gaap_HedgingDesignationDomain_B8933DB69A1F82C088ABE4B91EA5777F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_B7A0690FDB3A08CC4F75E4B91EA5CFE0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_B8933DB69A1F82C088ABE4B91EA5777F" xlink:to="loc_us-gaap_NondesignatedMember_B7A0690FDB3A08CC4F75E4B91EA5CFE0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_F14AA00D799C96993E4EE4B91EA56D65" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_32CC3EC7995AEA2E5ED5E4B91EA3C68F" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_F14AA00D799C96993E4EE4B91EA56D65" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_FCEFFA6451F63480F753E4B91EA53CC1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_F14AA00D799C96993E4EE4B91EA56D65" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_FCEFFA6451F63480F753E4B91EA53CC1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_FCEFFA6451F63480F753E4B91EA53CC1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_F14AA00D799C96993E4EE4B91EA56D65" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_FCEFFA6451F63480F753E4B91EA53CC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsMember" xlink:label="loc_us-gaap_OtherAssetsMember_22D2918AE7C323CC78AFE4B91EA5CD12" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_FCEFFA6451F63480F753E4B91EA53CC1" xlink:to="loc_us-gaap_OtherAssetsMember_22D2918AE7C323CC78AFE4B91EA5CD12" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AccruedExpensesAndOtherLiabilitiesMember" xlink:label="loc_iep_AccruedExpensesAndOtherLiabilitiesMember_3049BB71C430D72D8C8EE4B91EA58904" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_FCEFFA6451F63480F753E4B91EA53CC1" xlink:to="loc_iep_AccruedExpensesAndOtherLiabilitiesMember_3049BB71C430D72D8C8EE4B91EA58904" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_B932ACC852AD6A6B3AE7E4B91EA51123" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_32CC3EC7995AEA2E5ED5E4B91EA3C68F" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_B932ACC852AD6A6B3AE7E4B91EA51123" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_FA5D3E743D35C867E939E4B91EA6C9D4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_B932ACC852AD6A6B3AE7E4B91EA51123" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_FA5D3E743D35C867E939E4B91EA6C9D4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_FA5D3E743D35C867E939E4B91EA6C9D4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_B932ACC852AD6A6B3AE7E4B91EA51123" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_FA5D3E743D35C867E939E4B91EA6C9D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityContractMember" xlink:label="loc_us-gaap_EquityContractMember_295DB325550AB9A7CCFCE4B91EA6FF97" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_FA5D3E743D35C867E939E4B91EA6C9D4" xlink:to="loc_us-gaap_EquityContractMember_295DB325550AB9A7CCFCE4B91EA6FF97" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditRiskContractMember" xlink:label="loc_us-gaap_CreditRiskContractMember_4DE913994F7FB9E93F3DE4B91EA68379" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_FA5D3E743D35C867E939E4B91EA6C9D4" xlink:to="loc_us-gaap_CreditRiskContractMember_4DE913994F7FB9E93F3DE4B91EA68379" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommodityContractMember" xlink:label="loc_us-gaap_CommodityContractMember_8BB4F9FED9CA5977E4FFE4B91EA63C70" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_FA5D3E743D35C867E939E4B91EA6C9D4" xlink:to="loc_us-gaap_CommodityContractMember_8BB4F9FED9CA5977E4FFE4B91EA63C70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_41B4744A98B75B6C4840E4B91EA6B647" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DerivativesNotDesignatedAsHedgingInstrumentsFairValueLineItems_ACE909176B0E5E6A637DE4B91EA6015E" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_41B4744A98B75B6C4840E4B91EA6B647" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_F25ACCDBD55A1B3E3113E4B91EA6516D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DerivativesNotDesignatedAsHedgingInstrumentsFairValueLineItems_ACE909176B0E5E6A637DE4B91EA6015E" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_F25ACCDBD55A1B3E3113E4B91EA6516D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet" xlink:label="loc_us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet_94967106D52A29799584E4B91EA6A391" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DerivativesNotDesignatedAsHedgingInstrumentsFairValueLineItems_ACE909176B0E5E6A637DE4B91EA6015E" xlink:to="loc_us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet_94967106D52A29799584E4B91EA6A391" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssets" xlink:label="loc_us-gaap_DerivativeAssets_C2381A93ED1D6BA59C63E4B91EA6E039" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DerivativesNotDesignatedAsHedgingInstrumentsFairValueLineItems_ACE909176B0E5E6A637DE4B91EA6015E" xlink:to="loc_us-gaap_DerivativeAssets_C2381A93ED1D6BA59C63E4B91EA6E039" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaap_DerivativeLiabilities_3FFB7740259FC1E6B40CE4B91EA62F78" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DerivativesNotDesignatedAsHedgingInstrumentsFairValueLineItems_ACE909176B0E5E6A637DE4B91EA6015E" xlink:to="loc_us-gaap_DerivativeLiabilities_3FFB7740259FC1E6B40CE4B91EA62F78" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CollateralAlreadyPostedAggregateFairValue" xlink:label="loc_us-gaap_CollateralAlreadyPostedAggregateFairValue_707AE313B36490C015FDE4B91EA63B95" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_DerivativesNotDesignatedAsHedgingInstrumentsFairValueLineItems_ACE909176B0E5E6A637DE4B91EA6015E" xlink:to="loc_us-gaap_CollateralAlreadyPostedAggregateFairValue_707AE313B36490C015FDE4B91EA63B95" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/FinancialInstrumentsGainLossRecognizedOnDerivativesNotDesignatedAsHedgingTableDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_38F12073E870D221ED4EE4B9221479A2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_6B4ADBE8B6EF63117F3BE4B922117FA7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_38F12073E870D221ED4EE4B9221479A2" xlink:to="loc_us-gaap_DerivativeTable_6B4ADBE8B6EF63117F3BE4B922117FA7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_0569DF3E7F42DE27F96CE4B922117131" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_6B4ADBE8B6EF63117F3BE4B922117FA7" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_0569DF3E7F42DE27F96CE4B922117131" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_4ADE029171457F3AE10FE4B922114A39_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_0569DF3E7F42DE27F96CE4B922117131" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_4ADE029171457F3AE10FE4B922114A39_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_4ADE029171457F3AE10FE4B922114A39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_0569DF3E7F42DE27F96CE4B922117131" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_4ADE029171457F3AE10FE4B922114A39" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_NetGainFromInvestmentActivitiesMember" xlink:label="loc_iep_NetGainFromInvestmentActivitiesMember_75FACF098A7A12CD4325E4B922112A37" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_4ADE029171457F3AE10FE4B922114A39" xlink:to="loc_iep_NetGainFromInvestmentActivitiesMember_75FACF098A7A12CD4325E4B922112A37" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_9A820038B2212FCEDDA1E4B922121A07" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_6B4ADBE8B6EF63117F3BE4B922117FA7" xlink:to="loc_us-gaap_HedgingDesignationAxis_9A820038B2212FCEDDA1E4B922121A07" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_99B8A5CB1D0E9DA83404E4B92212505E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_9A820038B2212FCEDDA1E4B922121A07" xlink:to="loc_us-gaap_HedgingDesignationDomain_99B8A5CB1D0E9DA83404E4B92212505E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_99B8A5CB1D0E9DA83404E4B92212505E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_9A820038B2212FCEDDA1E4B922121A07" xlink:to="loc_us-gaap_HedgingDesignationDomain_99B8A5CB1D0E9DA83404E4B92212505E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_9B03561C0EFFD583902CE4B92212B9FE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_99B8A5CB1D0E9DA83404E4B92212505E" xlink:to="loc_us-gaap_NondesignatedMember_9B03561C0EFFD583902CE4B92212B9FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_75FFBF6638B022933C02E4B922129F78" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_6B4ADBE8B6EF63117F3BE4B922117FA7" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_75FFBF6638B022933C02E4B922129F78" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_256D0020B99D24A98F55E4B92212AE16_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_75FFBF6638B022933C02E4B922129F78" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_256D0020B99D24A98F55E4B92212AE16_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_256D0020B99D24A98F55E4B92212AE16" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_75FFBF6638B022933C02E4B922129F78" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_256D0020B99D24A98F55E4B92212AE16" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityContractMember" xlink:label="loc_us-gaap_EquityContractMember_3703A775EAFA108E6558E4B922125C4E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_256D0020B99D24A98F55E4B92212AE16" xlink:to="loc_us-gaap_EquityContractMember_3703A775EAFA108E6558E4B922125C4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditRiskContractMember" xlink:label="loc_us-gaap_CreditRiskContractMember_189E25D290DDDF62E5A9E4B922131663" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_256D0020B99D24A98F55E4B92212AE16" xlink:to="loc_us-gaap_CreditRiskContractMember_189E25D290DDDF62E5A9E4B922131663" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommodityContractMember" xlink:label="loc_us-gaap_CommodityContractMember_10BC4526DD271DA90AB1E4B92214A5C7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_256D0020B99D24A98F55E4B92212AE16" xlink:to="loc_us-gaap_CommodityContractMember_10BC4526DD271DA90AB1E4B92214A5C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet" xlink:label="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_8F991FDDDD236BDDCE29E4B922146B39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_38F12073E870D221ED4EE4B9221479A2" xlink:to="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_8F991FDDDD236BDDCE29E4B922146B39" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/FinancialInstrumentsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_9FD2C4A85AF7C6DA802921A42A71F559" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_6AAF6EDEFC0A2861ED3F21A42A69FA9A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_9FD2C4A85AF7C6DA802921A42A71F559" xlink:to="loc_us-gaap_DerivativeTable_6AAF6EDEFC0A2861ED3F21A42A69FA9A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_EF9F029D169ECCF3CA2621A42A6910E0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_6AAF6EDEFC0A2861ED3F21A42A69FA9A" xlink:to="loc_us-gaap_HedgingDesignationAxis_EF9F029D169ECCF3CA2621A42A6910E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_C9778F0B72BEE7294C8F21A42A695688_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_EF9F029D169ECCF3CA2621A42A6910E0" xlink:to="loc_us-gaap_HedgingDesignationDomain_C9778F0B72BEE7294C8F21A42A695688_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_C9778F0B72BEE7294C8F21A42A695688" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_EF9F029D169ECCF3CA2621A42A6910E0" xlink:to="loc_us-gaap_HedgingDesignationDomain_C9778F0B72BEE7294C8F21A42A695688" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_61895213CED59558361721A42A6AA2A0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_C9778F0B72BEE7294C8F21A42A695688" xlink:to="loc_us-gaap_NondesignatedMember_61895213CED59558361721A42A6AA2A0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_50D6B2664CA7673D088021A42A6B34E4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_6AAF6EDEFC0A2861ED3F21A42A69FA9A" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_50D6B2664CA7673D088021A42A6B34E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_AF6D64564C50DDEED8CE21A42A6BE451_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_50D6B2664CA7673D088021A42A6B34E4" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_AF6D64564C50DDEED8CE21A42A6BE451_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_AF6D64564C50DDEED8CE21A42A6BE451" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_50D6B2664CA7673D088021A42A6B34E4" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_AF6D64564C50DDEED8CE21A42A6BE451" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommodityContractMember" xlink:label="loc_us-gaap_CommodityContractMember_8CCE8885F51A8DA8F41221A42A706D15" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_AF6D64564C50DDEED8CE21A42A6BE451" xlink:to="loc_us-gaap_CommodityContractMember_8CCE8885F51A8DA8F41221A42A706D15" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_CommoditycontractsnotconsideredprobableofsettlementMember" xlink:label="loc_iep_CommoditycontractsnotconsideredprobableofsettlementMember_A76358E81950520D9B9C21A42A7044C7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_AF6D64564C50DDEED8CE21A42A6BE451" xlink:to="loc_iep_CommoditycontractsnotconsideredprobableofsettlementMember_A76358E81950520D9B9C21A42A7044C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_D91B71958FDC82C6CD5D21A42A70AAC7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_6AAF6EDEFC0A2861ED3F21A42A69FA9A" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_D91B71958FDC82C6CD5D21A42A70AAC7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_A4CFEFB93DA3CC17CA2F21A42A7003C2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_D91B71958FDC82C6CD5D21A42A70AAC7" xlink:to="loc_us-gaap_SegmentDomain_A4CFEFB93DA3CC17CA2F21A42A7003C2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_A4CFEFB93DA3CC17CA2F21A42A7003C2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_D91B71958FDC82C6CD5D21A42A70AAC7" xlink:to="loc_us-gaap_SegmentDomain_A4CFEFB93DA3CC17CA2F21A42A7003C2" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InvestmentSegmentMember" xlink:label="loc_iep_InvestmentSegmentMember_1A6859214630E3B0E6FE21A42A715C50" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_A4CFEFB93DA3CC17CA2F21A42A7003C2" xlink:to="loc_iep_InvestmentSegmentMember_1A6859214630E3B0E6FE21A42A715C50" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_EB3F7C1AD9BC8693D99021A42A71333B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_A4CFEFB93DA3CC17CA2F21A42A7003C2" xlink:to="loc_iep_EnergySegmentMember_EB3F7C1AD9BC8693D99021A42A71333B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetInvestmentHedgeDerivativeLiabilitiesAtFairValue" xlink:label="loc_us-gaap_NetInvestmentHedgeDerivativeLiabilitiesAtFairValue_E9842947A3575D0D1ED521A42A713478" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_9FD2C4A85AF7C6DA802921A42A71F559" xlink:to="loc_us-gaap_NetInvestmentHedgeDerivativeLiabilitiesAtFairValue_E9842947A3575D0D1ED521A42A713478" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditRiskDerivativeLiabilitiesAtFairValue" xlink:label="loc_us-gaap_CreditRiskDerivativeLiabilitiesAtFairValue_706DBD412D1071E4640C21A42A710757" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_9FD2C4A85AF7C6DA802921A42A71F559" xlink:to="loc_us-gaap_CreditRiskDerivativeLiabilitiesAtFairValue_706DBD412D1071E4640C21A42A710757" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmountVolume" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_7A1B71AFE9CE1B28FE3521A42A71E0CF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_9FD2C4A85AF7C6DA802921A42A71F559" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_7A1B71AFE9CE1B28FE3521A42A71E0CF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/FinancialInstrumentsNonDerivativeFinancialInstrumentsDesignatedAsHedgingDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/FinancialInstrumentsTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_3D5A8B530E2B5F25AAC68DD490DEF666" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_448C6F83D1E4523C87E8DB3B9A0C87B6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_3D5A8B530E2B5F25AAC68DD490DEF666" xlink:to="loc_us-gaap_DerivativeTable_448C6F83D1E4523C87E8DB3B9A0C87B6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EnergyAxis" xlink:label="loc_us-gaap_EnergyAxis_AEEE8DDA9E8F53048E167FAD78F86C60" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_448C6F83D1E4523C87E8DB3B9A0C87B6" xlink:to="loc_us-gaap_EnergyAxis_AEEE8DDA9E8F53048E167FAD78F86C60" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EnergyDomain" xlink:label="loc_us-gaap_EnergyDomain_737A6FD0A9FDC0915A1AA913EBC90F56_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EnergyAxis_AEEE8DDA9E8F53048E167FAD78F86C60" xlink:to="loc_us-gaap_EnergyDomain_737A6FD0A9FDC0915A1AA913EBC90F56_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EnergyDomain" xlink:label="loc_us-gaap_EnergyDomain_0BC177A27DF75F05AFFC4F9AD6BCA7A4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EnergyAxis_AEEE8DDA9E8F53048E167FAD78F86C60" xlink:to="loc_us-gaap_EnergyDomain_0BC177A27DF75F05AFFC4F9AD6BCA7A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_48FA4C13C56E5228B0373EC775697153" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_448C6F83D1E4523C87E8DB3B9A0C87B6" xlink:to="loc_us-gaap_VariableRateAxis_48FA4C13C56E5228B0373EC775697153" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_D291EA2DF61DB6CD30A7A913EBC9873E_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_48FA4C13C56E5228B0373EC775697153" xlink:to="loc_us-gaap_VariableRateDomain_D291EA2DF61DB6CD30A7A913EBC9873E_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_EF39623C322F5EE3B783C8E73114F118" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_48FA4C13C56E5228B0373EC775697153" xlink:to="loc_us-gaap_VariableRateDomain_EF39623C322F5EE3B783C8E73114F118" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_4DA6440F61185BDD8B839ACB054FDA05" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_448C6F83D1E4523C87E8DB3B9A0C87B6" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_4DA6440F61185BDD8B839ACB054FDA05" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_43F40B311075AE28C29DA913EBC94944_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4DA6440F61185BDD8B839ACB054FDA05" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_43F40B311075AE28C29DA913EBC94944_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_042B6D2577C75F168498C24E6D220DF6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4DA6440F61185BDD8B839ACB054FDA05" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_042B6D2577C75F168498C24E6D220DF6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PositionAxis" xlink:label="loc_us-gaap_PositionAxis_6F4C4AB20A3D57229A1AC7AF62515B42" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_448C6F83D1E4523C87E8DB3B9A0C87B6" xlink:to="loc_us-gaap_PositionAxis_6F4C4AB20A3D57229A1AC7AF62515B42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PositionDomain" xlink:label="loc_us-gaap_PositionDomain_FE1977DB805F84EB401DA913EBCA68AF_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PositionAxis_6F4C4AB20A3D57229A1AC7AF62515B42" xlink:to="loc_us-gaap_PositionDomain_FE1977DB805F84EB401DA913EBCA68AF_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PositionDomain" xlink:label="loc_us-gaap_PositionDomain_6FEFAC30D99454A8A5844FA0D6F43EF9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PositionAxis_6F4C4AB20A3D57229A1AC7AF62515B42" xlink:to="loc_us-gaap_PositionDomain_6FEFAC30D99454A8A5844FA0D6F43EF9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_D9D9097FF8FD5E6C91947ABC388AE5B9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_448C6F83D1E4523C87E8DB3B9A0C87B6" xlink:to="loc_us-gaap_RangeAxis_D9D9097FF8FD5E6C91947ABC388AE5B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_4DA80C47C154559BA5BFA913EBCAC865_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_D9D9097FF8FD5E6C91947ABC388AE5B9" xlink:to="loc_us-gaap_RangeMember_4DA80C47C154559BA5BFA913EBCAC865_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_927B183DEF9F54969E97A51E52B1AC63" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_D9D9097FF8FD5E6C91947ABC388AE5B9" xlink:to="loc_us-gaap_RangeMember_927B183DEF9F54969E97A51E52B1AC63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfOtherDerivativesNotDesignatedAsHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfOtherDerivativesNotDesignatedAsHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock_DA9C4AEDB7CE56C2AE86C28BB2AE7626" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3D5A8B530E2B5F25AAC68DD490DEF666" xlink:to="loc_us-gaap_ScheduleOfOtherDerivativesNotDesignatedAsHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock_DA9C4AEDB7CE56C2AE86C28BB2AE7626" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock_B443209111145BB9BA6499E2B77B7332" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3D5A8B530E2B5F25AAC68DD490DEF666" xlink:to="loc_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock_B443209111145BB9BA6499E2B77B7332" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNet" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNetDefiniteLivedAndIndefiniteLivedIntangibleAssetsTableDetails" xlink:type="extended">
    <link:loc xlink:href="iep-20180331.xsd#iep_FiniteLivedAndInfiniteLivedIntangibleAssetsBySegmentLineItems" xlink:label="loc_iep_FiniteLivedAndInfiniteLivedIntangibleAssetsBySegmentLineItems_CC9DE5CE1F8D5D4C951D6DDA902DDC46" xlink:type="locator" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsBySegmentTable" xlink:label="loc_iep_ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsBySegmentTable_F96A90FDC07B5500BB839D64016D2780" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_iep_FiniteLivedAndInfiniteLivedIntangibleAssetsBySegmentLineItems_CC9DE5CE1F8D5D4C951D6DDA902DDC46" xlink:to="loc_iep_ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsBySegmentTable_F96A90FDC07B5500BB839D64016D2780" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_9F76E83E5DCC55D9BD627F709BA36730" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsBySegmentTable_F96A90FDC07B5500BB839D64016D2780" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_9F76E83E5DCC55D9BD627F709BA36730" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_C173761C87D30441E825A913EB4232A8_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_9F76E83E5DCC55D9BD627F709BA36730" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_C173761C87D30441E825A913EB4232A8_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_754D84744746595BBE99FA60CDED9919" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_9F76E83E5DCC55D9BD627F709BA36730" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_754D84744746595BBE99FA60CDED9919" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="loc_us-gaap_CustomerRelationshipsMember_475F094B53B8568794CA1A1F6F1A3FB9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_754D84744746595BBE99FA60CDED9919" xlink:to="loc_us-gaap_CustomerRelationshipsMember_475F094B53B8568794CA1A1F6F1A3FB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_E381621EEF8E533FAB194AC6224ADC5D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_754D84744746595BBE99FA60CDED9919" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_E381621EEF8E533FAB194AC6224ADC5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeasesAcquiredInPlaceMember" xlink:label="loc_us-gaap_LeasesAcquiredInPlaceMember_2DE73F81C761576E9DE0AFB251265033" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_754D84744746595BBE99FA60CDED9919" xlink:to="loc_us-gaap_LeasesAcquiredInPlaceMember_2DE73F81C761576E9DE0AFB251265033" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_GasificationTechnologyMember" xlink:label="loc_iep_GasificationTechnologyMember_088B5EF4AFCE5C23AD85B0FEBBE56E9A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_754D84744746595BBE99FA60CDED9919" xlink:to="loc_iep_GasificationTechnologyMember_088B5EF4AFCE5C23AD85B0FEBBE56E9A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnclassifiedIndefinitelivedIntangibleAssetsMember" xlink:label="loc_us-gaap_UnclassifiedIndefinitelivedIntangibleAssetsMember_CF9B521B64AD582EACD736FC0575FE58" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_754D84744746595BBE99FA60CDED9919" xlink:to="loc_us-gaap_UnclassifiedIndefinitelivedIntangibleAssetsMember_CF9B521B64AD582EACD736FC0575FE58" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_57B0C8F2721D530B911CBFD13D26212C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsBySegmentTable_F96A90FDC07B5500BB839D64016D2780" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_57B0C8F2721D530B911CBFD13D26212C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_888500DE8A887E64F272A913EB433AB4_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_57B0C8F2721D530B911CBFD13D26212C" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_888500DE8A887E64F272A913EB433AB4_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_22A117D17B03561B8870096A4B723D4C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_57B0C8F2721D530B911CBFD13D26212C" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_22A117D17B03561B8870096A4B723D4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TrademarksAndTradeNamesMember" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_DAF2BEF2985F53D982EC4CA36C407940" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_22A117D17B03561B8870096A4B723D4C" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_DAF2BEF2985F53D982EC4CA36C407940" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_GamingLicenseMember" xlink:label="loc_iep_GamingLicenseMember_D985A907FECB54A097D401827CE43C6B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_22A117D17B03561B8870096A4B723D4C" xlink:to="loc_iep_GamingLicenseMember_D985A907FECB54A097D401827CE43C6B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FiniteLivedIntangibleAssetsGrossAndNetAbstract" xlink:label="loc_iep_FiniteLivedIntangibleAssetsGrossAndNetAbstract_F137F901E8DA5374AC8BAB6E40DE2959" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_FiniteLivedAndInfiniteLivedIntangibleAssetsBySegmentLineItems_CC9DE5CE1F8D5D4C951D6DDA902DDC46" xlink:to="loc_iep_FiniteLivedIntangibleAssetsGrossAndNetAbstract_F137F901E8DA5374AC8BAB6E40DE2959" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_7D9961293F9B599FBB8E9C1394AE6514" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_FiniteLivedIntangibleAssetsGrossAndNetAbstract_F137F901E8DA5374AC8BAB6E40DE2959" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_7D9961293F9B599FBB8E9C1394AE6514" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_233B868972CB586B8FA09281199802E5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_FiniteLivedIntangibleAssetsGrossAndNetAbstract_F137F901E8DA5374AC8BAB6E40DE2959" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_233B868972CB586B8FA09281199802E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_EE1F0AF4960D5D80BCD6F15ACBF81DC5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_FiniteLivedIntangibleAssetsGrossAndNetAbstract_F137F901E8DA5374AC8BAB6E40DE2959" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_EE1F0AF4960D5D80BCD6F15ACBF81DC5" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IndefiniteLivedIntangibleAssetsGrossAndNetAbstract" xlink:label="loc_iep_IndefiniteLivedIntangibleAssetsGrossAndNetAbstract_FC3A5EA8A582546992B162F12AF1CC06" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_FiniteLivedAndInfiniteLivedIntangibleAssetsBySegmentLineItems_CC9DE5CE1F8D5D4C951D6DDA902DDC46" xlink:to="loc_iep_IndefiniteLivedIntangibleAssetsGrossAndNetAbstract_FC3A5EA8A582546992B162F12AF1CC06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_4FA6BF4053F651DFAA7765DD0138CA2B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_IndefiniteLivedIntangibleAssetsGrossAndNetAbstract_FC3A5EA8A582546992B162F12AF1CC06" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_4FA6BF4053F651DFAA7765DD0138CA2B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNetGoodwillTableDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillLineItems" xlink:label="loc_us-gaap_GoodwillLineItems_02E8672F5E495C09814BEB6919DA5AF1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_2D563C948CA15264819BB0100EC00A7A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_02E8672F5E495C09814BEB6919DA5AF1" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_2D563C948CA15264819BB0100EC00A7A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_5ED3BF38B43B509D9A2A8714821CD3FE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_2D563C948CA15264819BB0100EC00A7A" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_5ED3BF38B43B509D9A2A8714821CD3FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_B3B3B502399713CE3B01A913EB4A049A_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_5ED3BF38B43B509D9A2A8714821CD3FE" xlink:to="loc_us-gaap_SegmentDomain_B3B3B502399713CE3B01A913EB4A049A_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_4C247F605A985A3D83C04CB9167BC107" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_5ED3BF38B43B509D9A2A8714821CD3FE" xlink:to="loc_us-gaap_SegmentDomain_4C247F605A985A3D83C04CB9167BC107" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_71D55AC73CA45B5D8F4A1904C7979A2F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4C247F605A985A3D83C04CB9167BC107" xlink:to="loc_iep_AutomotiveSegmentMember_71D55AC73CA45B5D8F4A1904C7979A2F" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RailcarSegmentMember" xlink:label="loc_iep_RailcarSegmentMember_04AE9A5747575EE383754B47B1605747" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4C247F605A985A3D83C04CB9167BC107" xlink:to="loc_iep_RailcarSegmentMember_04AE9A5747575EE383754B47B1605747" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FoodPackagingSegmentMember" xlink:label="loc_iep_FoodPackagingSegmentMember_744E1A189FD95D2BB72C7E9DE15948FF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4C247F605A985A3D83C04CB9167BC107" xlink:to="loc_iep_FoodPackagingSegmentMember_744E1A189FD95D2BB72C7E9DE15948FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillGross" xlink:label="loc_us-gaap_GoodwillGross_0BC9648A80A45A85A81A6B6B274CF7EA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_02E8672F5E495C09814BEB6919DA5AF1" xlink:to="loc_us-gaap_GoodwillGross_0BC9648A80A45A85A81A6B6B274CF7EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillImpairedAccumulatedImpairmentLoss" xlink:label="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_FF50C090AE3051F39E0C3C1F588BA436" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_02E8672F5E495C09814BEB6919DA5AF1" xlink:to="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_FF50C090AE3051F39E0C3C1F588BA436" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_7670A61E8A73519494AA777BF2A49B2A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_02E8672F5E495C09814BEB6919DA5AF1" xlink:to="loc_us-gaap_Goodwill_7670A61E8A73519494AA777BF2A49B2A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNetNarrativeDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/GoodwillAndIntangibleAssetsNetTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/IncomeTaxes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/IncomeTaxesIncomeTaxesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/InventoriesNetDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/InventoriesNetNotes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/InventoriesNetTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/InvestmentsAndRelatedMatters" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/InvestmentsAndRelatedMattersInvestmentSegmentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfInvestmentsLineItems_33F962B761F1DEE5200ADFB53626676D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfInvestmentsTable_A1382D018A7DC0CE9B3CDFB536265C18" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_33F962B761F1DEE5200ADFB53626676D" xlink:to="loc_us-gaap_ScheduleOfInvestmentsTable_A1382D018A7DC0CE9B3CDFB536265C18" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_9E0AE16D44E27C943380DFB53626503B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_A1382D018A7DC0CE9B3CDFB536265C18" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_9E0AE16D44E27C943380DFB53626503B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_2D403FDDD27478D7AFB4DFB53626AEE2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_9E0AE16D44E27C943380DFB53626503B" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_2D403FDDD27478D7AFB4DFB53626AEE2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_2D403FDDD27478D7AFB4DFB53626AEE2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_9E0AE16D44E27C943380DFB53626503B" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_2D403FDDD27478D7AFB4DFB53626AEE2" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_HertzMember" xlink:label="loc_iep_HertzMember_88A26EC553D134BA7193DFB536267B7D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_2D403FDDD27478D7AFB4DFB53626AEE2" xlink:to="loc_iep_HertzMember_88A26EC553D134BA7193DFB536267B7D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_HerbalifeMember" xlink:label="loc_iep_HerbalifeMember_483E66813F33B03E6178DFB536265B87" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_2D403FDDD27478D7AFB4DFB53626AEE2" xlink:to="loc_iep_HerbalifeMember_483E66813F33B03E6178DFB536265B87" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_E6CB17D16511366590B9DFB53626888B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_A1382D018A7DC0CE9B3CDFB536265C18" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_E6CB17D16511366590B9DFB53626888B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_5A4D9CE566A2C32BFFE2DFB53626F425_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_E6CB17D16511366590B9DFB53626888B" xlink:to="loc_us-gaap_SegmentDomain_5A4D9CE566A2C32BFFE2DFB53626F425_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_5A4D9CE566A2C32BFFE2DFB53626F425" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_E6CB17D16511366590B9DFB53626888B" xlink:to="loc_us-gaap_SegmentDomain_5A4D9CE566A2C32BFFE2DFB53626F425" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InvestmentSegmentMember" xlink:label="loc_iep_InvestmentSegmentMember_365114D6A1E88DFAC4CADFB5362662D5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5A4D9CE566A2C32BFFE2DFB53626F425" xlink:to="loc_iep_InvestmentSegmentMember_365114D6A1E88DFAC4CADFB5362662D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentSectorAxis" xlink:label="loc_invest_InvestmentSectorAxis_CB345EAF1D33DF4C5133DFB53626C0BB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_A1382D018A7DC0CE9B3CDFB536265C18" xlink:to="loc_invest_InvestmentSectorAxis_CB345EAF1D33DF4C5133DFB53626C0BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentSectorDomain" xlink:label="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_invest_InvestmentSectorAxis_CB345EAF1D33DF4C5133DFB53626C0BB" xlink:to="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentSectorDomain" xlink:label="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_invest_InvestmentSectorAxis_CB345EAF1D33DF4C5133DFB53626C0BB" xlink:to="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_BasicMaterialsMember" xlink:label="loc_iep_BasicMaterialsMember_E4DD66D218349DCDC097DFB5362622D3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:to="loc_iep_BasicMaterialsMember_E4DD66D218349DCDC097DFB5362622D3" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ConsumerNonCyclicalMember" xlink:label="loc_iep_ConsumerNonCyclicalMember_BD30838FD9D3296A8789DFB53626684C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:to="loc_iep_ConsumerNonCyclicalMember_BD30838FD9D3296A8789DFB53626684C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ConsumerCyclicalMember" xlink:label="loc_iep_ConsumerCyclicalMember_74015520273F4D73BD8BDFB53626D539" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:to="loc_iep_ConsumerCyclicalMember_74015520273F4D73BD8BDFB53626D539" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySectorMember" xlink:label="loc_iep_EnergySectorMember_89FB13975EC7F79A4C62DFB536266A9A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:to="loc_iep_EnergySectorMember_89FB13975EC7F79A4C62DFB536266A9A" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FinancialMember" xlink:label="loc_iep_FinancialMember_3E18ACF9A52E5F9B0DE3DFB536263FCB" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:to="loc_iep_FinancialMember_3E18ACF9A52E5F9B0DE3DFB536263FCB" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IndustrialMember" xlink:label="loc_iep_IndustrialMember_5F704F64E53180FE2E05DFB536263C8F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:to="loc_iep_IndustrialMember_5F704F64E53180FE2E05DFB536263C8F" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_TechnologyMember" xlink:label="loc_iep_TechnologyMember_0D24EEF4FA14FDDCAD1BDFB5362609A1" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:to="loc_iep_TechnologyMember_0D24EEF4FA14FDDCAD1BDFB5362609A1" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_OtherMember" xlink:label="loc_iep_OtherMember_19A79D8C5CB598B4EDAEDFB536260E64" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_invest_InvestmentSectorDomain_3A47AFC73706990D8CD6DFB536265B9E" xlink:to="loc_iep_OtherMember_19A79D8C5CB598B4EDAEDFB536260E64" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="loc_us-gaap_InvestmentTypeAxis_82B4DB120A6C0F05CD30DFB536260799" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_A1382D018A7DC0CE9B3CDFB536265C18" xlink:to="loc_us-gaap_InvestmentTypeAxis_82B4DB120A6C0F05CD30DFB536260799" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_5784D712B47B5A7ACF9CDFB53626E94A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_82B4DB120A6C0F05CD30DFB536260799" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_5784D712B47B5A7ACF9CDFB53626E94A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_5784D712B47B5A7ACF9CDFB53626E94A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_82B4DB120A6C0F05CD30DFB536260799" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_5784D712B47B5A7ACF9CDFB53626E94A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquitySecuritiesMember" xlink:label="loc_us-gaap_EquitySecuritiesMember_48BF8D395B4441CF003FDFB536267A54" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_5784D712B47B5A7ACF9CDFB53626E94A" xlink:to="loc_us-gaap_EquitySecuritiesMember_48BF8D395B4441CF003FDFB536267A54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtSecuritiesMember" xlink:label="loc_us-gaap_DebtSecuritiesMember_5298ACA15685A38DC151DFB53626B501" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_5784D712B47B5A7ACF9CDFB53626E94A" xlink:to="loc_us-gaap_DebtSecuritiesMember_5298ACA15685A38DC151DFB53626B501" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Investments" xlink:label="loc_us-gaap_Investments_13558FAFFA410EEB8BB6DFB536263230" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_33F962B761F1DEE5200ADFB53626676D" xlink:to="loc_us-gaap_Investments_13558FAFFA410EEB8BB6DFB536263230" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue" xlink:label="loc_us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue_261489254F5940E93597DFB536262D66" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_33F962B761F1DEE5200ADFB53626676D" xlink:to="loc_us-gaap_FinancialInstrumentsSoldNotYetPurchasedAtFairValue_261489254F5940E93597DFB536262D66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TradingSecuritiesUnrealizedHoldingGainLoss" xlink:label="loc_us-gaap_TradingSecuritiesUnrealizedHoldingGainLoss_707B905DFFA43BD0267DDFB536263A6F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_33F962B761F1DEE5200ADFB53626676D" xlink:to="loc_us-gaap_TradingSecuritiesUnrealizedHoldingGainLoss_707B905DFFA43BD0267DDFB536263A6F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_F10DBD611BD310248BACDFB5362663C8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_33F962B761F1DEE5200ADFB53626676D" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_F10DBD611BD310248BACDFB5362663C8" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Unrealizedgainonequitymethodinvestmentsunderfairvalueoption" xlink:label="loc_iep_Unrealizedgainonequitymethodinvestmentsunderfairvalueoption_1FE6256F17E6825F756ADFB536264400" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_33F962B761F1DEE5200ADFB53626676D" xlink:to="loc_iep_Unrealizedgainonequitymethodinvestmentsunderfairvalueoption_1FE6256F17E6825F756ADFB536264400" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FairValueOfEquityMethodInvestmentUnderFairValueOption" xlink:label="loc_iep_FairValueOfEquityMethodInvestmentUnderFairValueOption_1E1C51B2C7A3A72FEDB1DFB53626F91C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_33F962B761F1DEE5200ADFB53626676D" xlink:to="loc_iep_FairValueOfEquityMethodInvestmentUnderFairValueOption_1E1C51B2C7A3A72FEDB1DFB53626F91C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/InvestmentsAndRelatedMattersOtherSegmentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfInvestmentsLineItems_D0137C5A457D53569E2F3FAC40036E85" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfInvestmentsTable_581DCDCA0108563181F41FEE56007935" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_D0137C5A457D53569E2F3FAC40036E85" xlink:to="loc_us-gaap_ScheduleOfInvestmentsTable_581DCDCA0108563181F41FEE56007935" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_28264B80803D50D4A3B7A519E86EE541" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_581DCDCA0108563181F41FEE56007935" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_28264B80803D50D4A3B7A519E86EE541" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_4D51EF57B8C8FD382F79A913EC4EBB51_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_28264B80803D50D4A3B7A519E86EE541" xlink:to="loc_us-gaap_SegmentDomain_4D51EF57B8C8FD382F79A913EC4EBB51_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_6ABA8634D3C0591189D1F7798ABAA818" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_28264B80803D50D4A3B7A519E86EE541" xlink:to="loc_us-gaap_SegmentDomain_6ABA8634D3C0591189D1F7798ABAA818" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllOtherSegmentsMember" xlink:label="loc_us-gaap_AllOtherSegmentsMember_63D51A28A38B5E7EB87469C414C049C7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6ABA8634D3C0591189D1F7798ABAA818" xlink:to="loc_us-gaap_AllOtherSegmentsMember_63D51A28A38B5E7EB87469C414C049C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="loc_us-gaap_InvestmentTypeAxis_EE6A6E67F10752DA9E1CFF74CD4F2013" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_581DCDCA0108563181F41FEE56007935" xlink:to="loc_us-gaap_InvestmentTypeAxis_EE6A6E67F10752DA9E1CFF74CD4F2013" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_041395DED856D203A77FA913EC4E5ECA_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_EE6A6E67F10752DA9E1CFF74CD4F2013" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_041395DED856D203A77FA913EC4E5ECA_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_1469E2FDE2FC5AA8A3602538380D0AC0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_EE6A6E67F10752DA9E1CFF74CD4F2013" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_1469E2FDE2FC5AA8A3602538380D0AC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentsMember" xlink:label="loc_us-gaap_EquityMethodInvestmentsMember_87677FC9FA1857AFBDC74EAC063AAE31" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_1469E2FDE2FC5AA8A3602538380D0AC0" xlink:to="loc_us-gaap_EquityMethodInvestmentsMember_87677FC9FA1857AFBDC74EAC063AAE31" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherInvestmentsMember" xlink:label="loc_us-gaap_OtherInvestmentsMember_1F42FE27DC2B5050B83BECCB9965745E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_1469E2FDE2FC5AA8A3602538380D0AC0" xlink:to="loc_us-gaap_OtherInvestmentsMember_1F42FE27DC2B5050B83BECCB9965745E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Investments" xlink:label="loc_us-gaap_Investments_58E42B10767C5FE2A8A536EAA9C1B5B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_D0137C5A457D53569E2F3FAC40036E85" xlink:to="loc_us-gaap_Investments_58E42B10767C5FE2A8A536EAA9C1B5B0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/InvestmentsAndRelatedMattersTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfInvestmentsLineItems_48DF8C53637C505C8FB80C82129DFD89" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfInvestmentsTable_BA3F81BB044E5695BADA13332C1ED6BF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_48DF8C53637C505C8FB80C82129DFD89" xlink:to="loc_us-gaap_ScheduleOfInvestmentsTable_BA3F81BB044E5695BADA13332C1ED6BF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_F9C734F6AEA35225833B26579005B2BC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_BA3F81BB044E5695BADA13332C1ED6BF" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_F9C734F6AEA35225833B26579005B2BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_85FFAAF8CF1715025260A913EC82B362_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_F9C734F6AEA35225833B26579005B2BC" xlink:to="loc_us-gaap_SegmentDomain_85FFAAF8CF1715025260A913EC82B362_C3CB64FA40F25D5BAE380BC191C1E8A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_2B55218288FE56138381B176F065DFBC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_F9C734F6AEA35225833B26579005B2BC" xlink:to="loc_us-gaap_SegmentDomain_2B55218288FE56138381B176F065DFBC" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InvestmentSegmentMember" xlink:label="loc_iep_InvestmentSegmentMember_DE7BD791B25F589198FC1DF421F42254" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2B55218288FE56138381B176F065DFBC" xlink:to="loc_iep_InvestmentSegmentMember_DE7BD791B25F589198FC1DF421F42254" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllOtherSegmentsMember" xlink:label="loc_us-gaap_AllOtherSegmentsMember_C98D33078974524685BBF209976644C6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2B55218288FE56138381B176F065DFBC" xlink:to="loc_us-gaap_AllOtherSegmentsMember_C98D33078974524685BBF209976644C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentTableTextBlock" xlink:label="loc_invest_InvestmentTableTextBlock_FC728B7CE3DC553A96E71389166D63E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_48DF8C53637C505C8FB80C82129DFD89" xlink:to="loc_invest_InvestmentTableTextBlock_FC728B7CE3DC553A96E71389166D63E2" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/NetIncomePerLpUnit" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/NetIncomePerLpUnitDetails" xlink:type="extended">
    <link:loc xlink:href="iep-20180331.xsd#iep_EarningsPerLpUnitLineItems" xlink:label="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:type="locator" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ScheduleOfEarningsPerLpUnitTable" xlink:label="loc_iep_ScheduleOfEarningsPerLpUnitTable_13153867DE40D8CFE29502E8C6024A13" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_iep_ScheduleOfEarningsPerLpUnitTable_13153867DE40D8CFE29502E8C6024A13" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_76BA3A44CE4FFAE3E52A02E8F5FE1165" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_ScheduleOfEarningsPerLpUnitTable_13153867DE40D8CFE29502E8C6024A13" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_76BA3A44CE4FFAE3E52A02E8F5FE1165" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_61BF743C8065B6A0543502E8F84DEB5E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_76BA3A44CE4FFAE3E52A02E8F5FE1165" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_61BF743C8065B6A0543502E8F84DEB5E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_61BF743C8065B6A0543502E8F84DEB5E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_76BA3A44CE4FFAE3E52A02E8F5FE1165" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_61BF743C8065B6A0543502E8F84DEB5E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_412B8481578590128EB602E91BDDAE32" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_61BF743C8065B6A0543502E8F84DEB5E" xlink:to="loc_us-gaap_SubsequentEventMember_412B8481578590128EB602E91BDDAE32" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_MembersOrPartnersAxis" xlink:label="loc_iep_MembersOrPartnersAxis_132371F45237AEB9F8A902E8C6026420" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_ScheduleOfEarningsPerLpUnitTable_13153867DE40D8CFE29502E8C6024A13" xlink:to="loc_iep_MembersOrPartnersAxis_132371F45237AEB9F8A902E8C6026420" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PartnerNameDomain" xlink:label="loc_iep_PartnerNameDomain_D9AB917E5004F9160C4802E8C602C3C6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_iep_MembersOrPartnersAxis_132371F45237AEB9F8A902E8C6026420" xlink:to="loc_iep_PartnerNameDomain_D9AB917E5004F9160C4802E8C602C3C6_default" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PartnerNameDomain" xlink:label="loc_iep_PartnerNameDomain_D9AB917E5004F9160C4802E8C602C3C6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_iep_MembersOrPartnersAxis_132371F45237AEB9F8A902E8C6026420" xlink:to="loc_iep_PartnerNameDomain_D9AB917E5004F9160C4802E8C602C3C6" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PrincipalOwnersAndAffiliatesMember" xlink:label="loc_iep_PrincipalOwnersAndAffiliatesMember_F09F5EF90C6235284D7802E8C602B8F9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_PartnerNameDomain_D9AB917E5004F9160C4802E8C602C3C6" xlink:to="loc_iep_PrincipalOwnersAndAffiliatesMember_F09F5EF90C6235284D7802E8C602B8F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_693564C7209CA83EA3FC02E8C6021CC2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_NetIncomeLoss_693564C7209CA83EA3FC02E8C6021CC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossAllocatedToLimitedPartners" xlink:label="loc_us-gaap_NetIncomeLossAllocatedToLimitedPartners_6ED0CE40F0330D0B606F02E8C602DAB3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_NetIncomeLossAllocatedToLimitedPartners_6ED0CE40F0330D0B606F02E8C602DAB3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_C3790B022758D9CA5AEB02E8C6026319" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_C3790B022758D9CA5AEB02E8C6026319" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding_52889E7CA865441E214D02E8C6024DE1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstanding_52889E7CA865441E214D02E8C6024DE1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted" xlink:label="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_1A30A5FD9924A2AD893602E8C602E9C9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_NetIncomeLossNetOfTaxPerOutstandingLimitedPartnershipUnitDiluted_1A30A5FD9924A2AD893602E8C602E9C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted" xlink:label="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted_D5407CB53F5CB4DD0F1E02E8C602C8DD" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_WeightedAverageLimitedPartnershipUnitsOutstandingDiluted_D5407CB53F5CB4DD0F1E02E8C602C8DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_742A0A9F163938B55F1402E8C602D87D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_742A0A9F163938B55F1402E8C602D87D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_CB0A85B63D1A301EFF0802E8C6023195" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_CB0A85B63D1A301EFF0802E8C6023195" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerUnitDistribution" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerUnitDistribution_9478B631301424CBAD2002E8C602CA40" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerUnitDistribution_9478B631301424CBAD2002E8C602CA40" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_DistrubtionPayableToLpUnitHolders" xlink:label="loc_iep_DistrubtionPayableToLpUnitHolders_2F4EADBA63FA494622FF02E8C6028958" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_iep_DistrubtionPayableToLpUnitHolders_2F4EADBA63FA494622FF02E8C6028958" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_B3B9F57236BC4166350D02E8C602BCB0" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_EarningsPerLpUnitLineItems_E67A01AC056EF97B278802E8C602CFAF" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_B3B9F57236BC4166350D02E8C602BCB0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/NetIncomePerLpUnitTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/OtherIncomeLossNet" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/OtherIncomeLossNetDetails" xlink:type="extended">
    <link:loc xlink:href="iep-20180331.xsd#iep_ComponentOfOtherIncomeLossNetLineItems" xlink:label="loc_iep_ComponentOfOtherIncomeLossNetLineItems_A24D979695781F444BCB1CA93D99FB2B" xlink:type="locator" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ComponentOfOtherIncomeLossNeTable" xlink:label="loc_iep_ComponentOfOtherIncomeLossNeTable_6E8FE30E8761AE0774F31CA93D991A6D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetLineItems_A24D979695781F444BCB1CA93D99FB2B" xlink:to="loc_iep_ComponentOfOtherIncomeLossNeTable_6E8FE30E8761AE0774F31CA93D991A6D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ComponentOfOtherIncomeLossNetAxis" xlink:label="loc_iep_ComponentOfOtherIncomeLossNetAxis_3DCEF6B50E908BA93DF01CA93D99CB3C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_iep_ComponentOfOtherIncomeLossNeTable_6E8FE30E8761AE0774F31CA93D991A6D" xlink:to="loc_iep_ComponentOfOtherIncomeLossNetAxis_3DCEF6B50E908BA93DF01CA93D99CB3C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ComponentOfOtherIncomeLossNetNameDomain" xlink:label="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetAxis_3DCEF6B50E908BA93DF01CA93D99CB3C" xlink:to="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B_default" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ComponentOfOtherIncomeLossNetNameDomain" xlink:label="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetAxis_3DCEF6B50E908BA93DF01CA93D99CB3C" xlink:to="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_UnrealizedgainlossonderivativesMember" xlink:label="loc_iep_UnrealizedgainlossonderivativesMember_5EDD52554F4534CFA54D1CA93D999E1A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:to="loc_iep_UnrealizedgainlossonderivativesMember_5EDD52554F4534CFA54D1CA93D999E1A" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_OtherderivativegainMember" xlink:label="loc_iep_OtherderivativegainMember_1E96632411CE02D772B71CA93D99460B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:to="loc_iep_OtherderivativegainMember_1E96632411CE02D772B71CA93D99460B" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_LossOnDebtExtinguishmentMember" xlink:label="loc_iep_LossOnDebtExtinguishmentMember_554E931242EAF83CB8561CA93D9942FE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:to="loc_iep_LossOnDebtExtinguishmentMember_554E931242EAF83CB8561CA93D9942FE" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IncomelossfromnonconsolidatedaffiliatesMember" xlink:label="loc_iep_IncomelossfromnonconsolidatedaffiliatesMember_0E6F323BC86636D949881CA93D993A75" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:to="loc_iep_IncomelossfromnonconsolidatedaffiliatesMember_0E6F323BC86636D949881CA93D993A75" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ForeignCurrencyGainLossMember" xlink:label="loc_us-gaap_ForeignCurrencyGainLossMember_15BBA0E99DB85B3D71B11CA93D99E454" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:to="loc_us-gaap_ForeignCurrencyGainLossMember_15BBA0E99DB85B3D71B11CA93D99E454" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_GainlossondispositionsofassetsMember" xlink:label="loc_iep_GainlossondispositionsofassetsMember_8D42549D88D4434D37361CA93D997DC5" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:to="loc_iep_GainlossondispositionsofassetsMember_8D42549D88D4434D37361CA93D997DC5" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_NonservicepensionandotherpostretirementbenefitsexpenseMember" xlink:label="loc_iep_NonservicepensionandotherpostretirementbenefitsexpenseMember_7F96E8E4DC64BF6855781CA93D9980F9" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:to="loc_iep_NonservicepensionandotherpostretirementbenefitsexpenseMember_7F96E8E4DC64BF6855781CA93D9980F9" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_OtherIncomeLossNotSpecifiedMember" xlink:label="loc_iep_OtherIncomeLossNotSpecifiedMember_1C0ABC2258CC10970E1B1CA93D995EB0" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetNameDomain_1DD4E8BA3BEE27A6438A1CA93D99781B" xlink:to="loc_iep_OtherIncomeLossNotSpecifiedMember_1C0ABC2258CC10970E1B1CA93D995EB0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_5852377D5965624366691CA93D991DED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iep_ComponentOfOtherIncomeLossNetLineItems_A24D979695781F444BCB1CA93D99FB2B" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_5852377D5965624366691CA93D991DED" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/OtherIncomeLossNetTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/PensionsOtherPostRetirementBenefitsAndEmployeeBenefitPlans" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/PensionsOtherPostRetirementBenefitsAndEmployeeBenefitPlansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3EDB2B7A3D1B0FBACF8E1DE593DF63C2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_AA9391F713A2268BEAF81DE593DE5211" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3EDB2B7A3D1B0FBACF8E1DE593DF63C2" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_AA9391F713A2268BEAF81DE593DE5211" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_6296475D6010F4DEEC221DE593DF20B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_AA9391F713A2268BEAF81DE593DE5211" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_6296475D6010F4DEEC221DE593DF20B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_AE46AF895E3ECF130FFD1DE593DF71A1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_6296475D6010F4DEEC221DE593DF20B0" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_AE46AF895E3ECF130FFD1DE593DF71A1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_AE46AF895E3ECF130FFD1DE593DF71A1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_6296475D6010F4DEEC221DE593DF20B0" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_AE46AF895E3ECF130FFD1DE593DF71A1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_2BFDCF56BBF3C62AAE651DE593DF6EA7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_AE46AF895E3ECF130FFD1DE593DF71A1" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_2BFDCF56BBF3C62AAE651DE593DF6EA7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_EDCA2008D252CDA1CCDE1DE593DFCE22" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_AE46AF895E3ECF130FFD1DE593DF71A1" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_EDCA2008D252CDA1CCDE1DE593DFCE22" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_717B941BD1941F233E461DE593DF53A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3EDB2B7A3D1B0FBACF8E1DE593DF63C2" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_717B941BD1941F233E461DE593DF53A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_F5D17B7909D1849B3F791DE593E05B85" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3EDB2B7A3D1B0FBACF8E1DE593DF63C2" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_F5D17B7909D1849B3F791DE593E05B85" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_2CA69EA722A66AD67B581DE593E0EFFA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3EDB2B7A3D1B0FBACF8E1DE593DF63C2" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_2CA69EA722A66AD67B581DE593E0EFFA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_9C156CC7F8494F2015141DE593E02119" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3EDB2B7A3D1B0FBACF8E1DE593DF63C2" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_9C156CC7F8494F2015141DE593E02119" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_F6CB1FAEE12DFB861D541DE593E0417F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3EDB2B7A3D1B0FBACF8E1DE593DF63C2" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_F6CB1FAEE12DFB861D541DE593E0417F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1" xlink:label="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_E51E29119AF7DF5A94A11DE593E0622B" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3EDB2B7A3D1B0FBACF8E1DE593DF63C2" xlink:to="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_E51E29119AF7DF5A94A11DE593E0622B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_0CA8B3E2F9252B3B92641DE593E0BB2F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3EDB2B7A3D1B0FBACF8E1DE593DF63C2" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_0CA8B3E2F9252B3B92641DE593E0BB2F" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/PensionsOtherPostRetirementBenefitsAndEmployeeBenefitPlansTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/RelatedPartyTransactions" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/RelatedPartyTransactionsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_33B4488B1AB6617672280321CCAF4D48" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_8FB916F925B568F13FD10321CCAFC2E3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_33B4488B1AB6617672280321CCAF4D48" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_8FB916F925B568F13FD10321CCAFC2E3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_4F03F0621C2B4EB16DBD0321CCAF85A0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_8FB916F925B568F13FD10321CCAFC2E3" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_4F03F0621C2B4EB16DBD0321CCAF85A0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_1DE5182233DFC4FC17890321CCAF999D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_4F03F0621C2B4EB16DBD0321CCAF85A0" xlink:to="loc_us-gaap_RelatedPartyDomain_1DE5182233DFC4FC17890321CCAF999D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_1DE5182233DFC4FC17890321CCAF999D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_4F03F0621C2B4EB16DBD0321CCAF85A0" xlink:to="loc_us-gaap_RelatedPartyDomain_1DE5182233DFC4FC17890321CCAF999D" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PrincipalOwnersAndAffiliatesMember" xlink:label="loc_iep_PrincipalOwnersAndAffiliatesMember_A5F2C2AA062B14DF08200321CCAFAB07" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_1DE5182233DFC4FC17890321CCAF999D" xlink:to="loc_iep_PrincipalOwnersAndAffiliatesMember_A5F2C2AA062B14DF08200321CCAFAB07" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ConsolidatedVIEMember" xlink:label="loc_iep_ConsolidatedVIEMember_88D5A93902F07E5F10760321CCAFEBAA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_1DE5182233DFC4FC17890321CCAF999D" xlink:to="loc_iep_ConsolidatedVIEMember_88D5A93902F07E5F10760321CCAFEBAA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeMember" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_BC232B4FDD2DCDE36B5A0321CCAF0222" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_1DE5182233DFC4FC17890321CCAF999D" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_BC232B4FDD2DCDE36B5A0321CCAF0222" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AcfMember" xlink:label="loc_iep_AcfMember_95ACF55E798CAA7A086E0321CCAFF95C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_1DE5182233DFC4FC17890321CCAF999D" xlink:to="loc_iep_AcfMember_95ACF55E798CAA7A086E0321CCAFF95C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InsightPortfolioGroupLLCMember" xlink:label="loc_iep_InsightPortfolioGroupLLCMember_7658BB01E7191C95529E0321CCAF839A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_1DE5182233DFC4FC17890321CCAF999D" xlink:to="loc_iep_InsightPortfolioGroupLLCMember_7658BB01E7191C95529E0321CCAF839A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_BFE6DD930A37E4DB1AF30321CCAFE37A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_8FB916F925B568F13FD10321CCAFC2E3" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_BFE6DD930A37E4DB1AF30321CCAFE37A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_BFE6DD930A37E4DB1AF30321CCAFE37A" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_BFE6DD930A37E4DB1AF30321CCAFE37A" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InvestmentinfundsMember" xlink:label="loc_iep_InvestmentinfundsMember_3842C6AA5306A8AB1ED20321CCAF4023" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067" xlink:to="loc_iep_InvestmentinfundsMember_3842C6AA5306A8AB1ED20321CCAF4023" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_InvestmentbalanceinfundsMember" xlink:label="loc_iep_InvestmentbalanceinfundsMember_0C21A5A13A76C4AD46D40321CCAF48E0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067" xlink:to="loc_iep_InvestmentbalanceinfundsMember_0C21A5A13A76C4AD46D40321CCAF48E0" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_ExpenseSharingAgreementMember" xlink:label="loc_iep_ExpenseSharingAgreementMember_6DCAC794DF9101B4D8620321CCAFD5A3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067" xlink:to="loc_iep_ExpenseSharingAgreementMember_6DCAC794DF9101B4D8620321CCAFD5A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/sic/2011/sic-2011-01-31.xsd#sic_Z7600" xlink:label="loc_sic_Z7600_FE039BE12FD6B5419FEC0321CCAFD9D9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067" xlink:to="loc_sic_Z7600_FE039BE12FD6B5419FEC0321CCAFD9D9" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PurchasesfromrelatedpartyMember" xlink:label="loc_iep_PurchasesfromrelatedpartyMember_9782AB475ED6306577060321CCAFB9BC" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067" xlink:to="loc_iep_PurchasesfromrelatedpartyMember_9782AB475ED6306577060321CCAFB9BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingExpenseMember" xlink:label="loc_us-gaap_OperatingExpenseMember_29909D3B6E8A44DAE7F10321CCAFE2D7" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_D22B51DBE1742A3A73D60321CCAFB067" xlink:to="loc_us-gaap_OperatingExpenseMember_29909D3B6E8A44DAE7F10321CCAFE2D7" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_RelatedPartyTransactionBalance" xlink:label="loc_iep_RelatedPartyTransactionBalance_480E7C8DB916E6E806B70321CCAFD835" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_33B4488B1AB6617672280321CCAF4D48" xlink:to="loc_iep_RelatedPartyTransactionBalance_480E7C8DB916E6E806B70321CCAFD835" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_PercentagefairvalueofinvestmentsinFundsthatisattributabletoMr.Icahn" xlink:label="loc_iep_PercentagefairvalueofinvestmentsinFundsthatisattributabletoMr.Icahn_3752317DBFBB7204B01C0321CCAF480E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_33B4488B1AB6617672280321CCAF4D48" xlink:to="loc_iep_PercentagefairvalueofinvestmentsinFundsthatisattributabletoMr.Icahn_3752317DBFBB7204B01C0321CCAF480E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_F315A32FE14AB1B71C6E0321CCAFFFC8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_33B4488B1AB6617672280321CCAF4D48" xlink:to="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_F315A32FE14AB1B71C6E0321CCAFFFC8" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/SegmentReporting" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/SegmentReportingDisaggregationOfRevenueDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_BEE6ECDDC3B4F922494A2209586BE04D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_E09068D2C1A847BB57CA2209585BAB91" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_BEE6ECDDC3B4F922494A2209586BE04D" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_E09068D2C1A847BB57CA2209585BAB91" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelAxis" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_415644DEB69E61B346CC2209585B1B98" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_E09068D2C1A847BB57CA2209585BAB91" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_415644DEB69E61B346CC2209585B1B98" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_415644DEB69E61B346CC2209585B1B98" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_415644DEB69E61B346CC2209585B1B98" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PublicUtilitiesInventoryPetroleumProductsMember" xlink:label="loc_us-gaap_PublicUtilitiesInventoryPetroleumProductsMember_0BABE4AA28FAA2DE9E722209585BA173" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19" xlink:to="loc_us-gaap_PublicUtilitiesInventoryPetroleumProductsMember_0BABE4AA28FAA2DE9E722209585BA173" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_NitrogenfertilizerproductsMember" xlink:label="loc_iep_NitrogenfertilizerproductsMember_495719FD5EC3B8A4A6BF2209585B7F70" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19" xlink:to="loc_iep_NitrogenfertilizerproductsMember_495719FD5EC3B8A4A6BF2209585B7F70" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotivepartstooriginalequipmentmanufacturersandservicersMember" xlink:label="loc_iep_AutomotivepartstooriginalequipmentmanufacturersandservicersMember_BC1D08140B04A4B3B9B32209585BD0C7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19" xlink:to="loc_iep_AutomotivepartstooriginalequipmentmanufacturersandservicersMember_BC1D08140B04A4B3B9B32209585BD0C7" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AftermarketautomotivepartsandtiresMember" xlink:label="loc_iep_AftermarketautomotivepartsandtiresMember_1056CFBD02183F9E14EE2209585B6DAB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19" xlink:to="loc_iep_AftermarketautomotivepartsandtiresMember_1056CFBD02183F9E14EE2209585B6DAB" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveserviceslaborMember" xlink:label="loc_iep_AutomotiveserviceslaborMember_B528A372F03F18E19C3E2209585BA1BC" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19" xlink:to="loc_iep_AutomotiveserviceslaborMember_B528A372F03F18E19C3E2209585BA1BC" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_OthernetsalesMember" xlink:label="loc_iep_OthernetsalesMember_08F7882519158AC8759F2209585BEDF2" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_147F544436D4DFCEBA2E2209585BFC19" xlink:to="loc_iep_OthernetsalesMember_08F7882519158AC8759F2209585BEDF2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_4E29C2734AD6AD89414A2209585BBF02" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_E09068D2C1A847BB57CA2209585BAB91" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_4E29C2734AD6AD89414A2209585BBF02" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_F92DA9269300DECD5BA92209585B0EA3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_4E29C2734AD6AD89414A2209585BBF02" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_F92DA9269300DECD5BA92209585B0EA3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_F92DA9269300DECD5BA92209585B0EA3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_4E29C2734AD6AD89414A2209585BBF02" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_F92DA9269300DECD5BA92209585B0EA3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:label="loc_us-gaap_SalesRevenueNetMember_F259C3B03DE010667B162209585B1878" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_F92DA9269300DECD5BA92209585B0EA3" xlink:to="loc_us-gaap_SalesRevenueNetMember_F259C3B03DE010667B162209585B1878" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueServicesNetMember" xlink:label="loc_us-gaap_SalesRevenueServicesNetMember_B77CC5268ABCF3ADCC792209585B03E4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_F92DA9269300DECD5BA92209585B0EA3" xlink:to="loc_us-gaap_SalesRevenueServicesNetMember_B77CC5268ABCF3ADCC792209585B03E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_64552DA6DD90027B122E2209585B8387" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_E09068D2C1A847BB57CA2209585BAB91" xlink:to="loc_dei_LegalEntityAxis_64552DA6DD90027B122E2209585B8387" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_59E342C13F55848FD88B2209585B7F66_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_64552DA6DD90027B122E2209585B8387" xlink:to="loc_dei_EntityDomain_59E342C13F55848FD88B2209585B7F66_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_59E342C13F55848FD88B2209585B7F66" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_64552DA6DD90027B122E2209585B8387" xlink:to="loc_dei_EntityDomain_59E342C13F55848FD88B2209585B7F66" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FederalMogulMember" xlink:label="loc_iep_FederalMogulMember_775223FB3FFAC73AE0392209585BBEF9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_59E342C13F55848FD88B2209585B7F66" xlink:to="loc_iep_FederalMogulMember_775223FB3FFAC73AE0392209585BBEF9" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_IcahnAutomotiveGroupMember" xlink:label="loc_iep_IcahnAutomotiveGroupMember_E6695DF016FD8B355AD42209585B0508" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_59E342C13F55848FD88B2209585B7F66" xlink:to="loc_iep_IcahnAutomotiveGroupMember_E6695DF016FD8B355AD42209585B0508" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_2516D848E556F6C057722209585B7184" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_E09068D2C1A847BB57CA2209585BAB91" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_2516D848E556F6C057722209585B7184" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_48D02D511084C66412492209585B4ACC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2516D848E556F6C057722209585B7184" xlink:to="loc_us-gaap_SegmentDomain_48D02D511084C66412492209585B4ACC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_48D02D511084C66412492209585B4ACC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2516D848E556F6C057722209585B7184" xlink:to="loc_us-gaap_SegmentDomain_48D02D511084C66412492209585B4ACC" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_72259532FE89970F04782209585B2263" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_48D02D511084C66412492209585B4ACC" xlink:to="loc_iep_AutomotiveSegmentMember_72259532FE89970F04782209585B2263" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_7002463AFD9B64D2F5792209586BA4F1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_48D02D511084C66412492209585B4ACC" xlink:to="loc_iep_EnergySegmentMember_7002463AFD9B64D2F5792209586BA4F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_AC1A8E1180D4418E507F2209586BEF78" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_BEE6ECDDC3B4F922494A2209586BE04D" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_AC1A8E1180D4418E507F2209586BEF78" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/SegmentReportingPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/SegmentReportingTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_AA7F8CF92926C7B5CEDD21A428F163AA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_AB865CFBF25F102D1B1821A428F10341" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_AA7F8CF92926C7B5CEDD21A428F163AA" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_AB865CFBF25F102D1B1821A428F10341" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_55D66D6E52165E2C655821A428F13108" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_AB865CFBF25F102D1B1821A428F10341" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_55D66D6E52165E2C655821A428F13108" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_E54F8ADC13031DD63C8221A428F14D8F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_55D66D6E52165E2C655821A428F13108" xlink:to="loc_us-gaap_SegmentDomain_E54F8ADC13031DD63C8221A428F14D8F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_E54F8ADC13031DD63C8221A428F14D8F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_55D66D6E52165E2C655821A428F13108" xlink:to="loc_us-gaap_SegmentDomain_E54F8ADC13031DD63C8221A428F14D8F" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_AutomotiveSegmentMember" xlink:label="loc_iep_AutomotiveSegmentMember_357171AFFF8E5155E35921A428F1B5A0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_E54F8ADC13031DD63C8221A428F14D8F" xlink:to="loc_iep_AutomotiveSegmentMember_357171AFFF8E5155E35921A428F1B5A0" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_EnergySegmentMember" xlink:label="loc_iep_EnergySegmentMember_D38FA134BDCC850BEEFC21CCFD517163" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_E54F8ADC13031DD63C8221A428F14D8F" xlink:to="loc_iep_EnergySegmentMember_D38FA134BDCC850BEEFC21CCFD517163" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:label="loc_us-gaap_DisaggregationOfRevenueTableTextBlock_9867EC228E9D6AB0CC3621A428F159E3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_AA7F8CF92926C7B5CEDD21A428F163AA" xlink:to="loc_us-gaap_DisaggregationOfRevenueTableTextBlock_9867EC228E9D6AB0CC3621A428F159E3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/SubsequentEvents" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_356378F3108E9CD681821CA93D73035F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_90EC29794037CB4F1B9D1CA93D725B25" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_356378F3108E9CD681821CA93D73035F" xlink:to="loc_us-gaap_SubsequentEventTable_90EC29794037CB4F1B9D1CA93D725B25" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_25043592C82D779A2EB61CFBBACAF742" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_90EC29794037CB4F1B9D1CA93D725B25" xlink:to="loc_dei_LegalEntityAxis_25043592C82D779A2EB61CFBBACAF742" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_1E97A034D2451F530C241CFBBACA9011_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_25043592C82D779A2EB61CFBBACAF742" xlink:to="loc_dei_EntityDomain_1E97A034D2451F530C241CFBBACA9011_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_1E97A034D2451F530C241CFBBACA9011" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_25043592C82D779A2EB61CFBBACAF742" xlink:to="loc_dei_EntityDomain_1E97A034D2451F530C241CFBBACA9011" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_FederalMogulMember" xlink:label="loc_iep_FederalMogulMember_6948600B01E675CA9F181CFC02C6C17C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_1E97A034D2451F530C241CFBBACA9011" xlink:to="loc_iep_FederalMogulMember_6948600B01E675CA9F181CFC02C6C17C" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_TropicanaMember" xlink:label="loc_iep_TropicanaMember_A95F6A5DD2F0B0BC0ADA1CFBD69C5C0F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_1E97A034D2451F530C241CFBBACA9011" xlink:to="loc_iep_TropicanaMember_A95F6A5DD2F0B0BC0ADA1CFBD69C5C0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_F17B3A7CDAAD1E07A2ED1CA93D725DCD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_90EC29794037CB4F1B9D1CA93D725B25" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_F17B3A7CDAAD1E07A2ED1CA93D725DCD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_BA743A21F73901D3AFC71CA93D73971F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_F17B3A7CDAAD1E07A2ED1CA93D725DCD" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_BA743A21F73901D3AFC71CA93D73971F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_BA743A21F73901D3AFC71CA93D73971F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_F17B3A7CDAAD1E07A2ED1CA93D725DCD" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_BA743A21F73901D3AFC71CA93D73971F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_7BA0C914936721EF3F9D1CA93D73D188" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_BA743A21F73901D3AFC71CA93D73971F" xlink:to="loc_us-gaap_SubsequentEventMember_7BA0C914936721EF3F9D1CA93D73D188" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_9C202D2A0E22368F367B1CA93D7337F5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_356378F3108E9CD681821CA93D73035F" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_9C202D2A0E22368F367B1CA93D7337F5" xlink:type="arc" />
    <link:loc xlink:href="iep-20180331.xsd#iep_Aggregateconsiderationforbusinesstobedisposedof" xlink:label="loc_iep_Aggregateconsiderationforbusinesstobedisposedof_3DC7F525CEC5CFF45B8D1CFB538A41D4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_356378F3108E9CD681821CA93D73035F" xlink:to="loc_iep_Aggregateconsiderationforbusinesstobedisposedof_3DC7F525CEC5CFF45B8D1CFB538A41D4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.ielp.com/role/SupplementalCashFlowInformationDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/SupplementalCashFlowInformationNotes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.ielp.com/role/SupplementalCashFlowInformationTables" xlink:type="extended" />
</link:linkbase>
