-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 WZ95VDS3C2Rnly7/Qf34LzhePwMMAUR43qS4glfJN5tDOi47ZXsziSZRzO4pJFQY
 w3p87GR7Ic3QZjqK3h2+zQ==

<SEC-DOCUMENT>0000874015-08-000039.txt : 20080703
<SEC-HEADER>0000874015-08-000039.hdr.sgml : 20080703
<ACCEPTANCE-DATETIME>20080703160401
ACCESSION NUMBER:		0000874015-08-000039
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080701
FILED AS OF DATE:		20080703
DATE AS OF CHANGE:		20080703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PARSHALL B LYNNE
		CENTRAL INDEX KEY:			0001073385

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19125
		FILM NUMBER:		08938904

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		760-931-9200

	MAIL ADDRESS:	
		STREET 1:		1896 RUTHERFORD ROAD
		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:		1896 RUTHERFORD ROAD
		CITY:			CARLSBAD
		STATE:			CA
		ZIP:			92008
		BUSINESS PHONE:		7609319200

	MAIL ADDRESS:	
		STREET 1:		1896 RUTHERFORD ROAD
		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>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-07-01</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001073385</rptOwnerCik>
            <rptOwnerName>PARSHALL B LYNNE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ISIS PHARMACEUTICALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1896 RUTHERFORD ROAD</rptOwnerStreet2>
            <rptOwnerCity>CARLSBAD</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92008</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Director, COO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-07-01</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2008-07-01</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1285</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>11.798</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5448</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-07-03</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2008-07-03</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1338</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.9132</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4110</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Reporting 1,285 shares acquired under the Isis Pharmaceuticals, Inc. 2000 Employee Stock Purchase Plan on July 1, 2008.</footnote>
        <footnote id="F2">The sale reported on this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on 10/2/06.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>B. Lynne Parshall</signatureName>
        <signatureDate>2008-07-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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