-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 J2u3khsYoUcPfjwlsSz6z269KPj4JsBRc80QKkQioG7wR8owjH2BilVw0rJFHwc+
 RbM/vUvEGd7FsuREXruWPw==

<SEC-DOCUMENT>0000074208-05-000001.txt : 20050104
<SEC-HEADER>0000074208-05-000001.hdr.sgml : 20050104
<ACCEPTANCE-DATETIME>20050104150241
ACCESSION NUMBER:		0000074208-05-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050103
FILED AS OF DATE:		20050104
DATE AS OF CHANGE:		20050104

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WALLIS W MARK
		CENTRAL INDEX KEY:			0001195705

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10524
		FILM NUMBER:		05506484

	BUSINESS ADDRESS:	
		STREET 1:		UNITED DOMINION REALTY TRUST INC
		CITY:			HIGHLANDS RANCH
		STATE:			CO
		ZIP:			80129

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNITED DOMINION REALTY TRUST INC
		CENTRAL INDEX KEY:			0000074208
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				540857512
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		400 EAST CARY STREET
		CITY:			RICHMOND
		STATE:			VA
		ZIP:			23219-3802
		BUSINESS PHONE:		8047802691

	MAIL ADDRESS:	
		STREET 1:		400 EAST CARY STREET
		CITY:			RICHMOND
		STATE:			VA
		ZIP:			23219-3802

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	OLD DOMINION REAL ESTATE INVESTMENT TRUST
		DATE OF NAME CHANGE:	19850110

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	OLD DOMINION REIT ONE
		DATE OF NAME CHANGE:	19770921

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	OLD DOMINION REAL ESTATE INVESTMENT TRUS
		DATE OF NAME CHANGE:	19741216
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c0001195705d20050104f4f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-01-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000074208</issuerCik>
        <issuerName>UNITED DOMINION REALTY TRUST INC</issuerName>
        <issuerTradingSymbol>UDR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001195705</rptOwnerCik>
            <rptOwnerName>WALLIS W MARK</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>400 EAST CARY STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>RICHMOND</rptOwnerCity>
            <rptOwnerState>VA</rptOwnerState>
            <rptOwnerZipCode>23219</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Executive Vice Presiden</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>LLC Units</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-01-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-06-01</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>1988-08-08</value>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>20000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>170500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>LLC Units</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-01-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-06-01</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>1988-08-08</value>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>20000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Wallis Investments LLC</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person owns OPPSs issued by UDR Out-Performance I, LLC, a Virginia limited liability company (the &quot;LLC&quot;). The LLC's only assets are Operating Partnership Units (&quot;OPUs&quot;) owned by United Dominion Realty, L.P., a Delaware limited partnership (the &quot;Limited Partnership&quot;).</footnote>
        <footnote id="F2">Transfer of OPPSs to Wallis Investments LLC, a Colorado limited liability company, of which the reporting person is the sole manager, and of which the reporting person and his wife are the sole members.  The reporting person disclaims beneficial ownershp of OPPSs held by Wallis Investments LLC except to the extent of his pecuniary interest therein.</footnote>
        <footnote id="F3">Beginning on June 1, 2004, the OPPSs may be exchanged at the LLC's option for OPUs issued by the Limited Partnershp, and the total number of OPUs to be distributed shall be based upon a conversion factor set forth in the Amended and Restated Agreement of Limited Partnership.</footnote>
        <footnote id="F4">There is no expiration date for these securities.  The field is required for filing acceptance and the date is used for acceptance of filing purposes only.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>W. MARK WALLIS</signatureName>
        <signatureDate>2005-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
