-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 VcwHtZ1ysKBHYsjl06oCW5OZZLtBpb73j7mLJX/bu+T/zD59Qn3Oz2K6iCk6DBHG
 G2npIQ1LUQdCKvF2dSHAmg==

<SEC-DOCUMENT>0001097555-10-000002.txt : 20100813
<SEC-HEADER>0001097555-10-000002.hdr.sgml : 20100813
<ACCEPTANCE-DATETIME>20100813130327
ACCESSION NUMBER:		0001097555-10-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100810
FILED AS OF DATE:		20100813
DATE AS OF CHANGE:		20100813

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Pioneer Diversified High Income Trust
		CENTRAL INDEX KEY:			0001388126
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0430

	BUSINESS ADDRESS:	
		STREET 1:		60 STATE STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109
		BUSINESS PHONE:		617-742-7825

	MAIL ADDRESS:	
		STREET 1:		60 STATE STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Pioneer Diversified Income Opportunity Trust
		DATE OF NAME CHANGE:	20070129

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WEST STEPHEN
		CENTRAL INDEX KEY:			0001097555
		STATE OF INCORPORATION:			FL

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-22014
		FILM NUMBER:		101014200

	MAIL ADDRESS:	
		STREET 1:		60 STATE ST
		STREET 2:		19TH FL.
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109

	FORMER NAME:	
		FORMER CONFORMED NAME:	WEST STEVEN
		DATE OF NAME CHANGE:	19991022
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-08-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001388126</issuerCik>
        <issuerName>Pioneer Diversified High Income Trust</issuerName>
        <issuerTradingSymbol>HNW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001097555</rptOwnerCik>
            <rptOwnerName>WEST STEPHEN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>60 STATE ST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Trustee</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Pioneer Diversified High Income Trust</value>
            </securityTitle>
            <transactionDate>
                <value>2010-08-10</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2010-08-10</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>20.47</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Pioneer Diversified High Income Trust</value>
            </securityTitle>
            <transactionDate>
                <value>2010-08-10</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2010-08-10</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>400</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>20.48</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1900</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Jean M. Bradley - Chief Compliance Officer, by Power of Attorney</signatureName>
        <signatureDate>2010-08-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----