-----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,
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 5ZE1RgAmU4Ebf/8CUDzRbg==

<SEC-DOCUMENT>0001181431-05-019847.txt : 20050401
<SEC-HEADER>0001181431-05-019847.hdr.sgml : 20050401
<ACCEPTANCE-DATETIME>20050401175646
ACCESSION NUMBER:		0001181431-05-019847
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050330
FILED AS OF DATE:		20050401
DATE AS OF CHANGE:		20050401

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BAKER BROS CAPITAL GP LLC
		CENTRAL INDEX KEY:			0001244390
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-32405
		FILM NUMBER:		05726961

	MAIL ADDRESS:	
		STREET 1:		667 MADISON AVE 17TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10021

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BAKER JULIAN
		CENTRAL INDEX KEY:			0001087939

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-32405
		FILM NUMBER:		05726960

	BUSINESS ADDRESS:	
		STREET 1:		TISCH FAMILY INTERESTS
		STREET 2:		667 MADISON AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10021
		BUSINESS PHONE:		2125212420

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BAKER FELIX
		CENTRAL INDEX KEY:			0001087940

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-32405
		FILM NUMBER:		05726959

	BUSINESS ADDRESS:	
		STREET 1:		TISCH FAMILY INTERESTS
		STREET 2:		667 MADISON AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10021
		BUSINESS PHONE:		2125212420

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
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd74179.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-03-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001244390</rptOwnerCik>
            <rptOwnerName>BAKER BROS CAPITAL GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>667 MADISON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10021</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001087939</rptOwnerCik>
            <rptOwnerName>BAKER JULIAN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>667 MADISON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10021</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001087940</rptOwnerCik>
            <rptOwnerName>BAKER FELIX</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>667 MADISON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10021</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <transactionDate>
                <value>2005-03-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2344</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.9625</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>57673</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">In addition to Baker Bros. Capital (GP), LLC, this Form 4 is being filed jointly by Julian C. Baker and Felix J. Baker, each of whom has the same business address as Baker Bros. Capital (GP), LLC and may be deemed to have a pecuniary interest in securities owned by it. Because of certain relationships with other security holders of the Issuer, the Reporting Persons have filed on Schedule 13D as if they were a member of a group with such shareholders. (Continued in footnote 2.)</footnote>
        <footnote id="F2">However, the Reporting Persons disclaim that they and any other person or persons, including those persons with whom the Reporting Persons have filed a Schedule 13D in fact constitute a &quot;group&quot; for purposes of Section 13(d)(3) of the Securities Exchange Act of 1934, as amended, or Rule 13d-5 thereunder or that they are the beneficial owners of securities owned by any such other persons, and each of them disclaims beneficial ownership of securities reported herein except to the extent of their pecuniary interest, if any, therein. Felix J. Baker is a director of the Issuer.</footnote>
        <footnote id="F3">Represents 1,191 shares of common stock purchased directly by Baker Bros. Investments, L.P., and 1,153 shares of common stock purchased directly by Baker Bros. Investments II, L.P.</footnote>
        <footnote id="F4">Represents 29,545 shares of common stock owned directly by Baker Bros. Investments, L.P., and 28,128 shares of common stock owned directly by Baker Bros. Investments II, L.P. Baker Bros. Investments, L.P., and Baker Bros. Investments II, L.P., are each limited partnerships of which the sole general partner is Baker Bros. Capital, L.P., a limited partnership of which the sole general  partner is Baker Bros. Capital (GP), LLC. Felix J. Baker and Julian C. Baker are the controlling members of Baker Bros. Capital (GP), LLC.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Julian C. Baker, as Managing Member of Baker Bros. Capital (GP), LLC</signatureName>
        <signatureDate>2005-04-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Julian C. Baker</signatureName>
        <signatureDate>2005-04-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Felix J. Baker</signatureName>
        <signatureDate>2005-04-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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