-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Au+/hor2SRJ6ZqsthpLY7szTRfuDq4LjNCyixefrFyjAGWh2tUvxzNIwwhB3e1zE
 3hWKv1PfVWERpM1wUR7UOg==

<SEC-DOCUMENT>0001144204-05-013913.txt : 20050504
<SEC-HEADER>0001144204-05-013913.hdr.sgml : 20050504
<ACCEPTANCE-DATETIME>20050504154253
ACCESSION NUMBER:		0001144204-05-013913
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050429
FILED AS OF DATE:		20050504
DATE AS OF CHANGE:		20050504

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:			BAKER JULIAN
		CENTRAL INDEX KEY:			0001087939

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-32405
		FILM NUMBER:		05799033

	BUSINESS ADDRESS:	
		STREET 1:		TISCH FAMILY INTERESTS
		STREET 2:		667 MADISON AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10021
		BUSINESS PHONE:		212 521 2418

	MAIL ADDRESS:	
		STREET 1:		667 MADISON AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10021

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:		05799034

	BUSINESS ADDRESS:	
		STREET 1:		667 MADISON AVE 17TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10021
		BUSINESS PHONE:		212 521 2418

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

	FORMER NAME:	
		FORMER CONFORMED NAME:	BAKER BROS CAPITAL GP LLC
		DATE OF NAME CHANGE:	20030619

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:		05799035

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

	MAIL ADDRESS:	
		STREET 1:		667 MADISON AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10021
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>v017386_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-04-29</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>2005-04-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>133</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.9991</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>57806</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <transactionDate>
                <value>2005-04-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>257</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.9879</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>58063</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <transactionDate>
                <value>2005-04-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>17376</value>
                    <footnoteId id="F7"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>75439</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F8"/>
                </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 68 shares of common stock purchased directly by Baker Bros. Investments, L.P., and 65 shares of common stock
purchased directly by Baker Bros. Investments II, L.P.</footnote>
        <footnote id="F4">Represents 29,613 shares of common stock owned directly by Baker Bros. Investments, L.P., and 28,193 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>
        <footnote id="F5">Represents 131 shares of common stock purchased directly by Baker Bros. Investments, L.P., and 126 shares of common stock
purchased directly by Baker Bros. Investments II, L.P.</footnote>
        <footnote id="F6">Represents 29,744 shares of common stock owned directly by Baker Bros. Investments, L.P., and 28,319 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>
        <footnote id="F7">Represents 8,867 shares of common stock purchased directly by Baker Bros. Investments, L.P., and 8,509 shares of common stock
purchased directly by Baker Bros. Investments II, L.P.</footnote>
        <footnote id="F8">Represents 38,611 shares of common stock owned directly by Baker Bros. Investments, L.P., and 36,828 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>2005-05-03</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Julian C. Baker</signatureName>
        <signatureDate>2005-05-03</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Felix J. Baker</signatureName>
        <signatureDate>2005-05-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----