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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,
 N9dzZsdxk7Q80KXita5ygXhIl5mRsYzIyj3NS8P2fILZABwTBq4F4LlHQsaDy6oP
 JAmDzjdjyu+EMtx4P2mGaA==

<SEC-DOCUMENT>0000874015-04-000036.txt : 20040505
<SEC-HEADER>0000874015-04-000036.hdr.sgml : 20040505
<ACCEPTANCE-DATETIME>20040505160737
ACCESSION NUMBER:		0000874015-04-000036
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040427
FILED AS OF DATE:		20040505

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DE HAAN HANS A
		CENTRAL INDEX KEY:			0001287259

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19125
		FILM NUMBER:		04781721

	MAIL ADDRESS:	
		STREET 1:		ISIS PHARMACEUTICALS INC
		STREET 2:		2292 FARADAY AVE.
		CITY:			CARLSBAD
		STATE:			CA
		ZIP:			92008

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ISIS PHARMACEUTICALS INC
		CENTRAL INDEX KEY:			0000874015
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				330336973
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2292 FARADAY AVE
		CITY:			CARLSBAD
		STATE:			CA
		ZIP:			92008
		BUSINESS PHONE:		7609319200

	MAIL ADDRESS:	
		STREET 1:		2292 FARADAY AVE
		CITY:			CARLSBAD
		STATE:			CA
		ZIP:			92008
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-04-27</periodOfReport>

    <issuer>
        <issuerCik>0000874015</issuerCik>
        <issuerName>ISIS PHARMACEUTICALS INC</issuerName>
        <issuerTradingSymbol>ISIS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001287259</rptOwnerCik>
            <rptOwnerName>DE HAAN HANS A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2292 FARADAY AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CARLSBAD</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92008</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP, Drug Development</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-27</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2004-04-27</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5600</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.80</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Hans A. de Haan</signatureName>
        <signatureDate>2004-05-05</signatureDate>
    </ownerSignature>
</ownershipDocument>

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