Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Baker Bros. Capital (GP), LLC
   2. Issuer Name and Ticker or Trading Symbol
SEATTLE GENETICS INC /WA [SGEN] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
667 MADISON AVENUE		 3. Date of Earliest Transaction (Month/Day/Year)
04/29/2005
(Street)

NEW YORK, NY 10021		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock (1) (2) 04/29/2005   P   133 (3) A $ 3.9991 57,806 I See Footnote (4)
Common Stock (1) (2) 04/29/2005   P   257 (5) A $ 3.9879 58,063 I See Footnote (6)
Common Stock (1) (2) 04/29/2005   P   17,376 (7) A $ 4 75,439 I See Footnote (8)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Baker Bros. Capital (GP), LLC
667 MADISON AVENUE
NEW YORK, NY 10021		   X   X    
BAKER JULIAN
667 MADISON AVENUE
NEW YORK, NY 10021		     X    
BAKER FELIX
667 MADISON AVENUE
NEW YORK, NY 10021		   X   X    

Signatures

 /s/ Julian C. Baker, as Managing Member of Baker Bros. Capital (GP), LLC   05/03/2005
**Signature of Reporting Person Date
 /s/ Julian C. Baker   05/03/2005
**Signature of Reporting Person Date
 /s/ Felix J. Baker   05/03/2005
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) 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.)
(2) 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 "group" 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.
(3) 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.
(4) 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.
(5) 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.
(6) 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.
(7) 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.
(8) 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.

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