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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 C0Rwrh5ybCwSkGlMz7CJOg==

<SEC-DOCUMENT>0000765258-06-000039.txt : 20060424
<SEC-HEADER>0000765258-06-000039.hdr.sgml : 20060424
<ACCEPTANCE-DATETIME>20060424174821
ACCESSION NUMBER:		0000765258-06-000039
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20060424
FILED AS OF DATE:		20060424
DATE AS OF CHANGE:		20060424

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IMCLONE SYSTEMS INC
		CENTRAL INDEX KEY:			0000765258
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				042834797
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		180 VARICK STREET - 6TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10014
		BUSINESS PHONE:		646-638-5078

	MAIL ADDRESS:	
		STREET 1:		180 VARICK STREET - 6TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10014

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	IMCLONE SYSTEMS INC/DE
		DATE OF NAME CHANGE:	19940211

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TARNOWSKI S JOSEPH
		CENTRAL INDEX KEY:			0001177081

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19612
		FILM NUMBER:		06776154

	BUSINESS ADDRESS:	
		STREET 1:		IMCLONE SYSTEMS INC
		STREET 2:		180 VARICK STREET
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10014
		BUSINESS PHONE:		6466385078

	MAIL ADDRESS:	
		STREET 1:		IMCLONE SYSTEMS INCORPORATED
		STREET 2:		180 VARICK STREET, 6TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10014
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-04-24</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000765258</issuerCik>
        <issuerName>IMCLONE SYSTEMS INC</issuerName>
        <issuerTradingSymbol>IMCL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001177081</rptOwnerCik>
            <rptOwnerName>TARNOWSKI S JOSEPH</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BRISTOL-MYERS SQUIBB COMPANY</rptOwnerStreet1>
            <rptOwnerStreet2>ONE SQUIBB DRIVE</rptOwnerStreet2>
            <rptOwnerCity>NEW BRUNSWICK</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>08903</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>FORMER SVP, MFG, PD &amp; OPS</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
            </securityTitle>
            <transactionDate>
                <value>2006-04-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>6500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>37.16</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>26289</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>ERIK D. RAMANATHAN - BY POWER OF ATTORNEY</signatureName>
        <signatureDate>2006-04-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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