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<!--Created on: 11/5/2018 5:22:21 PM-->
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  <xsd:element name="CollaborativeArrangementAdditionalResearchTerm" id="xncr_CollaborativeArrangementAdditionalResearchTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CollaborationResearchAndLicensingAgreementsDisclosureAbstract" id="xncr_CollaborationResearchAndLicensingAgreementsDisclosureAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SupplementalCashFlowInformationCashPaidAbstract" id="xncr_SupplementalCashFlowInformationCashPaidAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EquityIncentivePlan2010Member" id="xncr_EquityIncentivePlan2010Member" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EquityIncentivePlan2013Member" id="xncr_EquityIncentivePlan2013Member" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DocumentAndEntityInformationAbstract" id="xncr_DocumentAndEntityInformationAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualPercentageIncreaseInSharesAuthorized" id="xncr_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualPercentageIncreaseInSharesAuthorized" type="num:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualIncreaseInSharesAuthorized" id="xncr_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualIncreaseInSharesAuthorized" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OptionAndLicenseAgreementMember" id="xncr_OptionAndLicenseAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ResearchLicenseAndCommercialization2009AgreementMember" id="xncr_ResearchLicenseAndCommercialization2009AgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AmgenIncMember" id="xncr_AmgenIncMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AlexionPharmaceuticalsIncMember" id="xncr_AlexionPharmaceuticalsIncMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CSLLimitedMember" id="xncr_CSLLimitedMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <element id="xncr_RevenueRecognitionMilestoneMethodPending" name="RevenueRecognitionMilestoneMethodPending" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_CollaborationAndLicenseAgreementMember" name="CollaborationAndLicenseAgreementMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element name="IncreaseDecreaseInDeferredRent" id="xncr_IncreaseDecreaseInDeferredRent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <element id="xncr_MarketableSecuritiesMember" name="MarketableSecuritiesMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_ResearchAndLicenseAgreement2015Member" name="ResearchAndLicenseAgreement2015Member" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element name="PreviousTargetsWhichBispecificTechnologyWillBeApplied" id="xncr_PreviousTargetsWhichBispecificTechnologyWillBeApplied" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="CollaborationAndLicensingProgramsAxis" id="xncr_CollaborationAndLicensingProgramsAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <element id="xncr_CollaborationAndLicensingProgramsDomain" name="CollaborationAndLicensingProgramsDomain" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_Cd38ProgramMember" name="Cd38ProgramMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_DiscoveryProgramMember" name="DiscoveryProgramMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_MonroviaMember" name="MonroviaMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_SanDiegoMember" name="SanDiegoMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_NovartisMember" name="NovartisMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_GlobalDiscoveryProgramMember" name="GlobalDiscoveryProgramMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_FcLicensesMember" name="FcLicensesMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_Xmab14045ProductMember" name="Xmab14045ProductMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_Xmab13676ProductMember" name="Xmab13676ProductMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_NumberOfDevelopmentStageProducts" name="NumberOfDevelopmentStageProducts" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_CollaborativeAgreementBispecificTechnologyAppliedNumberOfAntibodyTargets" name="CollaborativeAgreementBispecificTechnologyAppliedNumberOfAntibodyTargets" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_CollaborativeAgreementNonExclusiveLicenseProvidedNumberOfFcTechnologiesTargets" name="CollaborativeAgreementNonExclusiveLicenseProvidedNumberOfFcTechnologiesTargets" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_BispecificFcTechnologiesMember" name="BispecificFcTechnologiesMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_CollaborativeAgreementNumberOfPrograms" name="CollaborativeAgreementNumberOfPrograms" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_AggregateValueStockSold" name="AggregateValueStockSold" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_NumberOfCommercialLicenses" name="NumberOfCommercialLicenses" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_RightToSubstituteIdentifiedTargetPeriod" name="RightToSubstituteIdentifiedTargetPeriod" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_CashAndCashEquivalentsAndMarketableSecuritiesAmortizedCost" name="CashAndCashEquivalentsAndMarketableSecuritiesAmortizedCost" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_CollaborationMember" name="CollaborationMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_NumberOfBispecificDrugCandidates" name="NumberOfBispecificDrugCandidates" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_MilestonesOrRoyaltiesInTransactionPrice" name="MilestonesOrRoyaltiesInTransactionPrice" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_NumberOfAnnualInstallmentVestingPeriod" name="NumberOfAnnualInstallmentVestingPeriod" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_PriorRevenueRecognitionPeriod" name="PriorRevenueRecognitionPeriod" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="xncr_SaleOfAdditionalCommonStockTextBlock" name="SaleOfAdditionalCommonStockTextBlock" nillable="true" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
</xsd:schema>
