On January 18, 2008, Seattle Genetics, Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with J.P. Morgan Securities Inc. and UBS Securities LLC, as representatives for the underwriters named in Schedule 1 of the Underwriting Agreement (collectively, the “Underwriters”), relating to the offer and sale of 10,000,000 shares of the Company’s common stock, $0.001 par value per share at a price of $9.00 per share. The Underwriting Agreement also grants an option to the Underwritings to purchase an additional 1,500,000 shares of common stock to cover over-allotments, if any. The Underwriters’ obligations to purchase the shares of common stock is subject to the satisfaction of certain customary closing conditions, including receipt of legal opinions and approval of legal matters by their respective counsels. The offering is being made pursuant to the Company’s effective shelf registration statement on Form S-3 previously filed with the Securities and Exchange Commission and a prospectus supplement. The Underwriting Agreement is filed as Exhibit 1.1 to this report and is incorporated herein by reference. The description of the material terms of the Underwriting Agreement is qualified in its entirety by reference to such exhibit.

On January 18, 2008, the Company issued a press release announcing the issuance and sale of the shares and the proceeds of the underwritten public offering. A copy of the press release is attached as Exhibit 99.1 to this report.

The information in this Current Report on Form 8-K under the heading Item 7.01, “Regulation FD Disclosure,” including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference to such filing.

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

INDEX TO EXHIBITS