-----BEGIN PRIVACY-ENHANCED MESSAGE-----
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,
 L3QJxv8zK+5By5FW/M/8SruzfWkfL6/TbvEnzOtM3VPckR8Vej1Bdfv2CdZwhBKr
 vcj4rpj1GCdoHFHVFD2UYw==

<SEC-DOCUMENT>0001179110-03-006981.txt : 20030905
<SEC-HEADER>0001179110-03-006981.hdr.sgml : 20030905
<ACCEPTANCE-DATETIME>20030905144231
ACCESSION NUMBER:		0001179110-03-006981
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030905
FILED AS OF DATE:		20030905

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			KAISER MICHAEL D
		CENTRAL INDEX KEY:			0001250534

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-14023
		FILM NUMBER:		03883547

	BUSINESS ADDRESS:	
		STREET 1:		CORPORATE OFFICE PROPERTIES TR
		STREET 2:		8815 CENTRE PARK DR STE 400
		CITY:			COLUMBIA
		STATE:			MD
		ZIP:			21045
		BUSINESS PHONE:		4109927293

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CORPORATE OFFICE PROPERTIES TRUST
		CENTRAL INDEX KEY:			0000860546
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				232947217
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		8815 CENTRE PARK DR
		STREET 2:		SUITE 400
		CITY:			COLUMBIA
		STATE:			MD
		ZIP:			21045
		BUSINESS PHONE:		6105381800

	MAIL ADDRESS:	
		STREET 1:		8815 CENTRE PARK DR
		STREET 2:		SUITE 400
		CITY:			COLUMBIA
		STATE:			MD
		ZIP:			21045

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CORPORATE OFFICE PROPERTIES TRUST INC
		DATE OF NAME CHANGE:	19980105

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ROYALE INVESTMENTS INC
		DATE OF NAME CHANGE:	19930328

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ROYALE REIT INC
		DATE OF NAME CHANGE:	19600201
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-09-05</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000860546</issuerCik>
        <issuerName>CORPORATE OFFICE PROPERTIES TRUST</issuerName>
        <issuerTradingSymbol>OFC</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001250534</rptOwnerCik>
            <rptOwnerName>KAISER MICHAEL D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7005 HAWKSHEAD ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>TIMONIUM</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21093</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>1</isOther>
<officerTitle></officerTitle>
<otherText>Pres --Affiliate, CRM</otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Shares</value>
</securityTitle>
<transactionDate><value>2003-09-05</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>7500</value>
</transactionShares>
<transactionPricePerShare><value>18.70</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>56200</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</nonDerivativeTransaction>
</nonDerivativeTable>
<derivativeTable><derivativeTransaction><securityTitle><value>Exercised Options</value>
</securityTitle>
<conversionOrExercisePrice><value>7.25</value>
</conversionOrExercisePrice>
<transactionDate><value>2003-09-05</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>A</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>5000</value>
</transactionShares>
<transactionPricePerShare><value>7.25</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate><value>1999-09-27</value>
</exerciseDate>
<expirationDate><value>2008-09-27</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>5000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>50000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeTransaction>
<derivativeTransaction><securityTitle><value>Exercised Options</value>
</securityTitle>
<conversionOrExercisePrice><value>12.45</value>
</conversionOrExercisePrice>
<transactionDate><value>2003-09-05</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>A</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>2500</value>
</transactionShares>
<transactionPricePerShare><value>12.45</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate><value>2003-03-07</value>
</exerciseDate>
<expirationDate><value>2012-03-07</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Shares</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>2500</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>47500</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeTransaction>
</derivativeTable>
<footnotes></footnotes>
<ownerSignature><signatureName>Karen M. Singer, by Power of Attorney</signatureName>
<signatureDate>2003-09-05</signatureDate>
</ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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