-----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,
 BsFiAFk0b7FRQG9XGicOgbDMkFmP5EWKmZCgmv103Zt4ylxtwYiBQyykIJYxjPGv
 gCxA+taVlamee9mJgkJj7A==

<SEC-DOCUMENT>0001313799-05-000002.txt : 20050204
<SEC-HEADER>0001313799-05-000002.hdr.sgml : 20050204
<ACCEPTANCE-DATETIME>20050204155413
ACCESSION NUMBER:		0001313799-05-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050202
FILED AS OF DATE:		20050204
DATE AS OF CHANGE:		20050204

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Gonzalez Alejandro
		CENTRAL INDEX KEY:			0001313799

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-24274
		FILM NUMBER:		05577219

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		52554334556

	MAIL ADDRESS:	
		STREET 1:		RUBEN DARIO #223 5-A
		STREET 2:		CHAPULTEPEC MORALES
		CITY:			MEXICO D.F.
		STATE:			O5
		ZIP:			11570

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LA JOLLA PHARMACEUTICAL CO
		CENTRAL INDEX KEY:			0000920465
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				330361285
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		6455 NANCY RIDGE DR
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
		BUSINESS PHONE:		8584526600

	MAIL ADDRESS:	
		STREET 1:		6455 NANCY RIDGE DR
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
</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>2005-02-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000920465</issuerCik>
        <issuerName>LA JOLLA PHARMACEUTICAL CO</issuerName>
        <issuerTradingSymbol>LJPC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001313799</rptOwnerCik>
            <rptOwnerName>Gonzalez Alejandro</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>RUBEN DARIO #223 5-A</rptOwnerStreet1>
            <rptOwnerStreet2>CHAPULTEPEC MORALES</rptOwnerStreet2>
            <rptOwnerCity>MEXICO D.F.</rptOwnerCity>
            <rptOwnerState>O5</rptOwnerState>
            <rptOwnerZipCode>11570</rptOwnerZipCode>
            <rptOwnerStateDescription>MEXICO</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-02-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>77000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.5</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6864720</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Alejandro Gonzalez</signatureName>
        <signatureDate>2005-02-04</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----