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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Wa+v2fXf/UW9jeOyiT5Fu3WpHXE9Cpo4tZS1tbkKdknP8GSgdwaydr1f7WyiHXYq
 2GUSzz8z2h3k6m+2TuXHUg==

<SEC-DOCUMENT>0000074208-04-000007.txt : 20040217
<SEC-HEADER>0000074208-04-000007.hdr.sgml : 20040216
<ACCEPTANCE-DATETIME>20040217150128
ACCESSION NUMBER:		0000074208-04-000007
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040212
FILED AS OF DATE:		20040217

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TOOMEY THOMAS W
		CENTRAL INDEX KEY:			0001195697

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10524
		FILM NUMBER:		04607763

	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>c0001195697d20040217f4f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-02-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001195697</rptOwnerCik>
            <rptOwnerName>TOOMEY THOMAS W</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>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-02-12</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>51463</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>18.46</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>440075</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>THOMAS W TOOMEY</signatureName>
        <signatureDate>2004-02-17</signatureDate>
    </ownerSignature>
</ownershipDocument>

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