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 Brothers Life Sciences 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, 17TH FLOOR		 3. Date of Earliest Transaction (Month/Day/Year)
04/25/2006
(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) 04/25/2006   J(2)   353,150 D $ 0 0 I See Footnote (3)
Common Stock 04/25/2006   J(2)   49,807 D $ 0 0 I See footnote (4)
Common Stock 04/25/2006   J(2)   45,090 D $ 0 0 I See footnote (5)
Common Stock 04/25/2006   J(2)   448,047 A $ 0 682,908 I See footnote (6)

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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
Common Stock Warrants (right to buy) $ 6.25 04/25/2006   J(2)     312,162 07/08/2003 12/31/2011 Common Stock 312,162 $ 0 0 I See footnote (3)
Common Stock Warrants (right to buy) $ 6.25 04/25/2006   J(2)     42,981 07/08/2003 12/31/2011 Common Stock 42,981 $ 0 0 I See footnote (4)
Common Stock Warrants (right to buy) $ 6.25 04/25/2006   J(2)   355,143   07/08/2003 12/31/2011 Common Stock 355,143 $ 0 355,143 I See footnote (6)
Series A Convertible Preferred Stock (7) 04/25/2006   J(2)     249,730   (8)   (9) Common Stock 2,497,300 $ 0 0 I See footnote (3)
Series A Convertible Preferred Stock (7) 04/25/2006   J(2)     34,385   (8)   (9) Common Stock 343,850 $ 0 0 I See footnote (4)
Series A Convertible Preferred Stock (7) 04/25/2006   J(2)   284,115     (8)   (9) Common Stock 2,841,150 $ 0 284,115 I See footnote (6)

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Baker Brothers Life Sciences Capital (GP), LLC
667 MADISON AVENUE
17TH FLOOR
NEW YORK, NY 10021		   X   X    
Baker Biotech Capital II (GP), LLC
667 MADISON AVE
17TH FLOOR
NEW YORK, NY 10021		     X    
Baker Biotech Capital II (Z) (GP), LLC
667 MADISON AVENUE
17TH FLOOR
NEW YORK, NY 10021		     X    
Baker Biotech Capital III (Z) (GP), LLC
667 MADISON AVENUE
17TH FLOOR
NEW YORK, NY 10021		     X    
BAKER JULIAN
667 MADISON AVENUE
17TH FLOOR
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 Biotech Capital II (GP), LLC   04/28/2006
**Signature of Reporting Person Date
 /s/ Julian C. Baker, as Managing Member of Baker Biotech Capital II (Z) (GP), LLC   04/28/2006
**Signature of Reporting Person Date
 /s/ Julian C. Baker, as Managing Member of Baker Biotech Capital III (Z) (GP), LLC   04/28/2006
**Signature of Reporting Person Date
 /s/ Julian C. Baker, as Managing Member of Baker Brothers Life Sciences Capital (GP), LLC   04/28/2006
**Signature of Reporting Person Date
 /s/ Julian C. Baker   04/28/2006
**Signature of Reporting Person Date
 /s/ Felix J. Baker   04/28/2006
**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) See Note 1 in Exhibit 99.1.
(2) See Note 1 in Exhibit 99.1.
(3) See Note 1 in Exhibit 99.1.
(4) See Note 1 in Exhibit 99.1.
(5) See Note 1 in Exhibit 99.1.
(6) See Note 1 in Exhibit 99.1.
(7) See Note 1 in Exhibit 99.1.
(8) See Note 1 in Exhibit 99.1.
(9) See Note 1 in Exhibit 99.1.

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