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  <schemaVersion>X0202</schemaVersion>
  <headerData>
    <submissionType>13F-HR</submissionType>
    <filerInfo>
      <liveTestFlag>LIVE</liveTestFlag>
      <flags/>
      <filer>
        <credentials>
          <cik>0001068855</cik>
          <ccc>XXXXXXXX</ccc>
        </credentials>
      </filer>
      <periodOfReport>03-31-2026</periodOfReport>
    </filerInfo>
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    <coverPage>
      <reportCalendarOrQuarter>03-31-2026</reportCalendarOrQuarter>
      <isAmendment>false</isAmendment>
      <filingManager>
        <name>Asset Management One Co., Ltd.</name>
        <address>
          <ns1:street1>TEKKO BUILDING</ns1:street1>
          <ns1:street2>8-2, MARUNOUCHI 1-CHOME, CHIYODA-KU</ns1:street2>
          <ns1:city>TOKYO</ns1:city>
          <ns1:stateOrCountry>M0</ns1:stateOrCountry>
          <ns1:zipCode>100-0005</ns1:zipCode>
        </address>
      </filingManager>
      <reportType>13F HOLDINGS REPORT</reportType>
      <form13FFileNumber>028-07332</form13FFileNumber>
      <crdNumber>000110843</crdNumber>
      <secFileNumber>801-55047</secFileNumber>
      <provideInfoForInstruction5>N</provideInfoForInstruction5>
    </coverPage>
    <signatureBlock>
      <name>GOTO, Ryoichi</name>
      <title>Head of Legal &amp; Compliance</title>
      <phone>81-3-6774-5648</phone>
      <signature>GOTO, Ryoichi</signature>
      <city>Tokyo</city>
      <stateOrCountry>M0</stateOrCountry>
      <signatureDate>05-07-2026</signatureDate>
    </signatureBlock>
    <summaryPage>
      <otherIncludedManagersCount>0</otherIncludedManagersCount>
      <tableEntryTotal>911</tableEntryTotal>
      <tableValueTotal>33910663838</tableValueTotal>
      <isConfidentialOmitted>false</isConfidentialOmitted>
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