<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-04-30</periodOfReport>


    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001166258</issuerCik>
        <issuerName>PIONEER HIGH INCOME TRUST</issuerName>
        <issuerTradingSymbol>PHH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001172361</rptOwnerCik>
            <rptOwnerName>GERACI DANIEL T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Trustee</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>


    <ownerSignature>
        <signatureName>daniel t. geraci</signatureName>
        <signatureDate>2003-04-30</signatureDate>
    </ownerSignature>

</ownershipDocument>
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4
2003-04-30
1
0001166258
PIONEER HIGH INCOME TRUST
PHH
0001172361
GERACI DANIEL T
1
0
0
1
Trustee
daniel t. geraci
2003-04-30