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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 MPHwngsikluOMlb6Up5v6YvNgSy5/xiMRqQPK0ekCH52+nrCnqZ6xvXj4xdKFdeV
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<SEC-DOCUMENT>0001140361-08-011715.txt : 20080509
<SEC-HEADER>0001140361-08-011715.hdr.sgml : 20080509
<ACCEPTANCE-DATETIME>20080509131846
ACCESSION NUMBER:		0001140361-08-011715
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080508
FILED AS OF DATE:		20080509
DATE AS OF CHANGE:		20080509

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BAGALAY JOHN E JR
		CENTRAL INDEX KEY:			0001022838
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14879
		FILM NUMBER:		08817363

	MAIL ADDRESS:	
		STREET 1:		C/O DECORIZE INC
		STREET 2:		1938 E. PHELPS ST
		CITY:			SPRINGFIELD
		STATE:			MO
		ZIP:			65802

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CYTOGEN CORP
		CENTRAL INDEX KEY:			0000725058
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				222322400
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		650 COLLEGE RD EAST STE 3100
		CITY:			PRINCETON
		STATE:			NJ
		ZIP:			08540
		BUSINESS PHONE:		6099878200

	MAIL ADDRESS:	
		STREET 1:		650 COLLEGE RD EAST STE 3100
		CITY:			PRINCETON
		STATE:			NJ
		ZIP:			08540
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-05-08</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000725058</issuerCik>
        <issuerName>CYTOGEN CORP</issuerName>
        <issuerTradingSymbol>CYTO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001022838</rptOwnerCik>
            <rptOwnerName>BAGALAY JOHN E JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CYTOGEN CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>650 COLLEGE ROAD EAST, STE 3100</rptOwnerStreet2>
            <rptOwnerCity>PRINCETON</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>08540</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-05-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-05-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These shares were converted into the right to receive the merger consideration, as provided in the Agreement and Plan of Merger, dated March 10, 2008, by and among Cytogen Corporation, EUSA Pharma, Inc. and EUSA Pharma (USA), Inc. (the &quot;Merger&quot;) of $0.62 per share.</footnote>
        <footnote id="F2">This restricted stock became fully vested and exercisable upon consummation of the Merger.  In connection with the Merger, these shares were cancelled in exchange for the right to receive $0.62 per share.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ John E. Bagalay</signatureName>
        <signatureDate>2008-05-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----