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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 AzEgh/ltKepb1JPs3rsJi3YnV6FJOWIVgT9QCMab1YA1IX7fJkqrWa+ykdC07x7Y
 SWSM5+EyrHm/6O1isXwpsQ==

<SEC-DOCUMENT>0001104659-04-006588.txt : 20040305
<SEC-HEADER>0001104659-04-006588.hdr.sgml : 20040305
<ACCEPTANCE-DATETIME>20040305165412
ACCESSION NUMBER:		0001104659-04-006588
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040205
FILED AS OF DATE:		20040305

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SEATTLE GENETICS INC /WA
		CENTRAL INDEX KEY:			0001060736
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				911874389
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		21823 30TH DRIVE SE
		STREET 2:		SUITE
		CITY:			BOTHELL
		STATE:			WA
		ZIP:			98021
		BUSINESS PHONE:		4255274000

	MAIL ADDRESS:	
		STREET 1:		21823 30TH DRIVE SE
		STREET 2:		SUITE
		CITY:			BOTHELL
		STATE:			WA
		ZIP:			98021

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CASCADE INVESTMENT LLC
		CENTRAL INDEX KEY:			0001052192
		STATE OF INCORPORATION:			WA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	333-50266
		FILM NUMBER:		04652696

	BUSINESS ADDRESS:	
		STREET 1:		2365 CARILLON POINT
		CITY:			KIRKLAND
		STATE:			WA
		ZIP:			98033
		BUSINESS PHONE:		4258030720

	MAIL ADDRESS:	
		STREET 1:		2365 CARILLON POINT
		CITY:			KIRKLAND
		STATE:			WA
		ZIP:			98033
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-02-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001060736</issuerCik>
        <issuerName>SEATTLE GENETICS INC /WA</issuerName>
        <issuerTradingSymbol>SGEN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001052192</rptOwnerCik>
            <rptOwnerName>CASCADE INVESTMENT LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2365 CARILLON POINT</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>KIRKLAND</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>98033</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Formerly a 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3521088</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Cascade Investment, L.L.C. made no purchase or sale of securities causing the filing of this report.  This report is being filed as notification that Cascade is no longer a 10% holder of the Company's securities due to the Company's issuance of additional shares.  Therefore, Cascade is no longer a Section 16 filer with respect to the Company.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Michael Larson, Manager</signatureName>
        <signatureDate>2004-03-02</signatureDate>
    </ownerSignature>
</ownershipDocument>

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