﻿<?xml version="1.0" encoding="utf-8"?>
<Return xmlns="http://www.irs.gov/efile" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" returnVersion="2024v5.1">
  <ReturnHeader binaryAttachmentCnt="0">
    <ReturnTs>2026-08-13T11:58:15+00:00</ReturnTs>
    <TaxPeriodEndDt>2025-09-30</TaxPeriodEndDt>
    <PreparerFirmGrp>
      <PreparerFirmEIN>135565207</PreparerFirmEIN>
      <PreparerFirmName>
        <BusinessNameLine1Txt>KPMG LLP</BusinessNameLine1Txt>
      </PreparerFirmName>
      <PreparerUSAddress>
        <AddressLine1Txt>401 UNION STREET SUITE 2800</AddressLine1Txt>
        <CityNm>SEATTLE</CityNm>
        <StateAbbreviationCd>WA</StateAbbreviationCd>
        <ZIPCd>98101</ZIPCd>
      </PreparerUSAddress>
    </PreparerFirmGrp>
    <ReturnTypeCd>990EZ</ReturnTypeCd>
    <TaxPeriodBeginDt>2024-10-01</TaxPeriodBeginDt>
    <Filer>
      <EIN>270053014</EIN>
      <BusinessName>
        <BusinessNameLine1Txt>SEATTLE CHILDREN'S HOSPITAL (DBA MITOCHONDRIAL RESEARCH GUILD)</BusinessNameLine1Txt>
      </BusinessName>
      <BusinessNameControlTxt>SEAT</BusinessNameControlTxt>
      <PhoneNum>2068842351</PhoneNum>
      <USAddress>
        <AddressLine1Txt>PO BOX 5371 MS 818-FI</AddressLine1Txt>
        <CityNm>SEATTLE</CityNm>
        <StateAbbreviationCd>WA</StateAbbreviationCd>
        <ZIPCd>981455005</ZIPCd>
      </USAddress>
    </Filer>
    <BusinessOfficerGrp>
      <PersonNm>AILEEN KELLY</PersonNm>
      <PersonTitleTxt>EX-OFFICIO GUILD ASSN EXEC DIRECTOR</PersonTitleTxt>
      <SignatureDt>2026-08-13</SignatureDt>
      <DiscussWithPaidPreparerInd>true</DiscussWithPaidPreparerInd>
    </BusinessOfficerGrp>
    <IRSResponsiblePrtyInfoCurrInd>true</IRSResponsiblePrtyInfoCurrInd>
    <PreparerPersonGrp>
      <PreparerPersonNm>KATHRYN J OKIMOTO</PreparerPersonNm>
      <PTIN>P00746598</PTIN>
      <PhoneNum>2069134000</PhoneNum>
    </PreparerPersonGrp>
    <TaxYr>2024</TaxYr>
    <BuildTS>2025-03-06 01:10:19Z</BuildTS>
  </ReturnHeader>
  <ReturnData documentCnt="4">
    <IRS990EZ documentId="IRS990EZ" softwareId="24020961" softwareVersionNum="2024v5.1">
      <GroupExemptionNum>8041</GroupExemptionNum>
      <MethodOfAccountingCashInd>X</MethodOfAccountingCashInd>
      <WebsiteAddressTxt>WWW.NWMITO-RESEARCH.ORG</WebsiteAddressTxt>
      <Organization501c3Ind referenceDocumentId="IRS990ScheduleA">X</Organization501c3Ind>
      <TypeOfOrganizationAssocInd>X</TypeOfOrganizationAssocInd>
      <GrossReceiptsAmt>39212</GrossReceiptsAmt>
      <InfoInScheduleOPartIInd>X</InfoInScheduleOPartIInd>
      <ContributionsGiftsGrantsEtcAmt>39212</ContributionsGiftsGrantsEtcAmt>
      <GainOrLossFromSaleOfAssetsAmt>0</GainOrLossFromSaleOfAssetsAmt>
      <SpecialEventsNetIncomeLossAmt>0</SpecialEventsNetIncomeLossAmt>
      <GrossProfitLossSlsOfInvntryAmt>0</GrossProfitLossSlsOfInvntryAmt>
      <OtherRevenueTotalAmt>0</OtherRevenueTotalAmt>
      <TotalRevenueAmt>39212</TotalRevenueAmt>
      <GrantsAndSimilarAmountsPaidAmt>38000</GrantsAndSimilarAmountsPaidAmt>
      <OtherExpensesTotalAmt>1019</OtherExpensesTotalAmt>
      <TotalExpensesAmt>39019</TotalExpensesAmt>
      <ExcessOrDeficitForYearAmt>193</ExcessOrDeficitForYearAmt>
      <NetAssetsOrFundBalancesBOYAmt>4052</NetAssetsOrFundBalancesBOYAmt>
      <OtherChangesInNetAssetsAmt>0</OtherChangesInNetAssetsAmt>
      <NetAssetsOrFundBalancesEOYAmt>4245</NetAssetsOrFundBalancesEOYAmt>
      <CashSavingsAndInvestmentsGrp>
        <BOYAmt>4052</BOYAmt>
        <EOYAmt>4245</EOYAmt>
      </CashSavingsAndInvestmentsGrp>
      <LandAndBuildingsGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </LandAndBuildingsGrp>
      <OtherAssetsTotalDetail>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </OtherAssetsTotalDetail>
      <Form990TotalAssetsGrp>
        <BOYAmt>4052</BOYAmt>
        <EOYAmt>4245</EOYAmt>
      </Form990TotalAssetsGrp>
      <SumOfTotalLiabilitiesGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </SumOfTotalLiabilitiesGrp>
      <NetAssetsOrFundBalancesGrp>
        <BOYAmt>4052</BOYAmt>
        <EOYAmt>4245</EOYAmt>
      </NetAssetsOrFundBalancesGrp>
      <InfoInScheduleOPartIIIInd>X</InfoInScheduleOPartIIIInd>
      <PrimaryExemptPurposeTxt>THE MITOCHONDRIAL RESEARCH GUILD WAS FOUNDED IN 2003 AS A SPECIAL INTEREST GUILD OF THE SEATTLE CHILDREN'S HOSPITAL (A 501(C)(3) TAX-EXEMPT HOSPITAL). THE MITOCHONDRIAL RESEARCH GUILD SEEKS TO FUND RESEARCH, PROMOTE AWARENESS, AND OFFER SUPPORT TO FAMILIES IN THE NORTHWEST AFFECTED BY MITOCHONDRIAL DISEASE.</PrimaryExemptPurposeTxt>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>(CONTINUED ON SCHEDULE O)</DescriptionProgramSrvcAccomTxt>
        <GrantsAndAllocationsAmt>38000</GrantsAndAllocationsAmt>
        <ProgramServiceExpensesAmt>38000</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <TotalProgramServiceExpensesAmt>38000</TotalProgramServiceExpensesAmt>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>HEATHER OWENS</PersonNm>
        <TitleTxt>PRESIDENT</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>2.000</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>DIANE NIELSEN</PersonNm>
        <TitleTxt>TREASURER</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>3.000</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>SANDY RUDY</PersonNm>
        <TitleTxt>SECRETARY</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.000</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>AILEEN KELLY</PersonNm>
        <TitleTxt>EX-OFFICIO GUILD ASSN EXEC DIRECTOR</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>0.100</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <InfoInScheduleOPartVInd>X</InfoInScheduleOPartVInd>
      <ActivitiesNotPreviouslyRptInd>false</ActivitiesNotPreviouslyRptInd>
      <ChgMadeToOrgnzngDocNotRptInd>false</ChgMadeToOrgnzngDocNotRptInd>
      <OrganizationHadUBIInd>false</OrganizationHadUBIInd>
      <SubjectToProxyTaxInd>false</SubjectToProxyTaxInd>
      <OrganizationDissolvedEtcInd>false</OrganizationDissolvedEtcInd>
      <Form1120PolFiledInd>false</Form1120PolFiledInd>
      <MadeLoansToFromOfficersInd>false</MadeLoansToFromOfficersInd>
      <LoansToFromOfficersAmt>0</LoansToFromOfficersAmt>
      <EngagedInExcessBenefitTransInd>false</EngagedInExcessBenefitTransInd>
      <ProhibitedTaxShelterTransInd>false</ProhibitedTaxShelterTransInd>
      <BooksInCareOfDetail>
        <BusinessName>
          <BusinessNameLine1Txt>SAMANTHA SLOANE</BusinessNameLine1Txt>
        </BusinessName>
        <USAddress>
          <AddressLine1Txt>818 STEWART ST 8TH FLOOR</AddressLine1Txt>
          <CityNm>SEATTLE</CityNm>
          <StateAbbreviationCd>WA</StateAbbreviationCd>
          <ZIPCd>98101</ZIPCd>
        </USAddress>
        <PhoneNum>2068842351</PhoneNum>
      </BooksInCareOfDetail>
      <ForeignFinancialAccountInd>false</ForeignFinancialAccountInd>
      <ForeignOfficeInd>false</ForeignOfficeInd>
      <DonorAdvisedFndsInd>false</DonorAdvisedFndsInd>
      <OperateHospitalInd>false</OperateHospitalInd>
      <TanningServicesProvidedInd>false</TanningServicesProvidedInd>
      <RelatedOrganizationCtrlEntInd>false</RelatedOrganizationCtrlEntInd>
      <TransactionWithControlEntInd>false</TransactionWithControlEntInd>
      <PoliticalCampaignActyInd>false</PoliticalCampaignActyInd>
      <LobbyingActivitiesInd>false</LobbyingActivitiesInd>
      <SchoolOperatingInd>false</SchoolOperatingInd>
      <TrnsfrExmptNonChrtblRltdOrgInd>false</TrnsfrExmptNonChrtblRltdOrgInd>
      <FiledScheduleAInd>true</FiledScheduleAInd>
    </IRS990EZ>
    <IRS990ScheduleA documentId="IRS990ScheduleA" softwareId="24020961" softwareVersionNum="2024v5.1">
      <PublicOrganization170Ind>X</PublicOrganization170Ind>
      <GiftsGrantsContriRcvd170Grp>
        <CurrentTaxYearMinus4YearsAmt>144735</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>132500</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>124258</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>83242</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>39212</CurrentTaxYearAmt>
        <TotalAmt>523947</TotalAmt>
      </GiftsGrantsContriRcvd170Grp>
      <TaxRevLeviedOrgnztnlBnft170Grp>
        <TotalAmt>0</TotalAmt>
      </TaxRevLeviedOrgnztnlBnft170Grp>
      <GovtFurnSrvcFcltsVl170Grp>
        <TotalAmt>0</TotalAmt>
      </GovtFurnSrvcFcltsVl170Grp>
      <TotalCalendarYear170Grp>
        <CurrentTaxYearMinus4YearsAmt>144735</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>132500</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>124258</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>83242</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>39212</CurrentTaxYearAmt>
        <TotalAmt>523947</TotalAmt>
      </TotalCalendarYear170Grp>
      <SubstantialContributorsTotAmt>221755</SubstantialContributorsTotAmt>
      <PublicSupportTotal170Amt>302192</PublicSupportTotal170Amt>
      <GrossInvestmentIncome170Grp>
        <TotalAmt>0</TotalAmt>
      </GrossInvestmentIncome170Grp>
      <UnrelatedBusinessNetIncm170Grp>
        <TotalAmt>0</TotalAmt>
      </UnrelatedBusinessNetIncm170Grp>
      <OtherIncome170Grp>
        <CurrentTaxYearMinus4YearsAmt>0</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>0</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>0</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>0</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>0</CurrentTaxYearAmt>
        <TotalAmt>0</TotalAmt>
      </OtherIncome170Grp>
      <TotalSupportAmt>523947</TotalSupportAmt>
      <GrossReceiptsRltdActivitiesAmt>0</GrossReceiptsRltdActivitiesAmt>
      <PublicSupportCY170Pct>0.57676</PublicSupportCY170Pct>
      <PublicSupportPY170Pct>0.56779</PublicSupportPY170Pct>
      <ThirtyThrPctSuprtTestsCY170Ind>X</ThirtyThrPctSuprtTestsCY170Ind>
    </IRS990ScheduleA>
    <IRS990ScheduleB documentId="IRS990ScheduleB" softwareId="24020961" softwareVersionNum="2024v5.1">
      <ContributorInformationGrp>
        <ContributorNum>RESTRICTED</ContributorNum>
        <ContributorBusinessName>
          <BusinessNameLine1>RESTRICTED</BusinessNameLine1>
        </ContributorBusinessName>
        <ContributorUSAddress>
          <AddressLine1>RESTRICTED</AddressLine1>
          <AddressLine2>RESTRICTED</AddressLine2>
          <City>RESTRICTED</City>
          <State>RESTRICTED</State>
          <ZIPCode>RESTRICTED</ZIPCode>
        </ContributorUSAddress>
        <TotalContributionsAmt>RESTRICTED</TotalContributionsAmt>
      </ContributorInformationGrp>
    </IRS990ScheduleB>
    <IRS990ScheduleO documentId="IRS990ScheduleO" softwareId="24020961" softwareVersionNum="2024v5.1">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990-EZ, PART I, LINE 10 GRANTS PAID</FormAndLineReferenceDesc>
        <ExplanationTxt>ACTIVITY:MITOCHONDRIAL RESEARCH FUND;GRANTEE NAME:SEATTLE CHILDREN'S GUILD ASSOCIATION;GRANTEE ADDRESS:PO BOX 5371, MS: 818-FI , SEATTLE, WA, 98145-5005, US;AMOUNT:38000;RELATIONSHIP:NONE;</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990-EZ, PART I, LINE 16 OTHER EXPENSES</FormAndLineReferenceDesc>
        <ExplanationTxt>CREDIT CARD AND BANK FEES - 63; OFFICE SUPPLIES &amp; EXPENSES - 956;</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990-EZ, PART III, EXEMPT PURPOSE PRIMARY EXEMPT PURPOSE</FormAndLineReferenceDesc>
        <ExplanationTxt>THE MITOCHONDRIAL RESEARCH GUILD WAS FOUNDED IN 2003 AS A SPECIAL INTEREST GUILD OF THE SEATTLE CHILDREN'S HOSPITAL (A 501(C)(3) TAX-EXEMPT HOSPITAL). THE MITOCHONDRIAL RESEARCH GUILD SEEKS TO FUND RESEARCH, PROMOTE AWARENESS, AND OFFER SUPPORT TO FAMILIES IN THE NORTHWEST AFFECTED BY MITOCHONDRIAL DISEASE.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990-EZ, PART III, LINE 28, DESCRIPTION PROGRAM SERVICE ACCOMPLISHMENTS</FormAndLineReferenceDesc>
        <ExplanationTxt>THE MITOCHONDRIAL RESEARCH GUILD IS A MEMBER OF THE SEATTLE CHILDREN'S GUILD ASSOCIATION, A TAX-EXEMPT FUNDRAISING ENTITY OF SEATTLE CHILDREN'S HOSPITAL. THE HOSPITAL PROVIDES PEDIATRIC PATIENT CARE, MEDICAL RESEARCH, TEACHING OF PEDIATRIC RESIDENTS AND OTHER HEALTHCARE PROVIDERS, AS WELL AS ADVOCACY FOR CHILDREN IN THE PACIFIC NORTHWEST. THE MITOCHONDRIAL RESEARCH GUILD DIRECTED DONATIONS TO THE MITOCHONDRIAL RESEARCH FUND OF THE HOSPITAL. THESE FUNDS FULFILL THE GUILD'S MISSION BY SUPPORTING MITOCHONDRIAL RESEARCH ACTIVITIES.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990-EZ, PART V, LINE 33A INFORMATION REGARDING PERSONAL BENEFIT CONTRACTS</FormAndLineReferenceDesc>
        <ExplanationTxt>THE ORGANIZATION DID NOT, DURING THE YEAR, RECEIVE ANY FUNDS, DIRECTLY, OR INDIRECTLY, TO PAY PREMIUMS ON A PERSONAL BENEFIT CONTRACT. THE ORGANIZATION, DID NOT, DURING THE YEAR, PAY ANY PREMIUMS, DIRECTLY, OR INDIRECTLY, ON A PERSONAL BENEFIT CONTRACT.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
  </ReturnData>
</Return>