Exhibit 5.1

		140 Scott Drive
		Menlo Park, California 94025
		Tel: +1.650.328.4600 Fax: +1.650.463.2600
		www.lw.com
		FIRM / AFFILIATE OFFICES
		Abu Dhabi		Moscow
		Barcelona		Munich
		Beijing		New Jersey
		Brussels		New York
		Chicago		Orange County
		Doha		Paris
January 21, 2010		Dubai		Rome
		Frankfurt		San Diego
		Hamburg		San Francisco
		Hong Kong		Shanghai
		London		Silicon Valley
		Los Angeles		Singapore
		Madrid		Tokyo
		Milan		Washington, D.C.

InterMune, Inc.

3280 Bayshore Boulevard

Brisbane, CA 94005

Common Stock, par value $0.001 per share.

Ladies and Gentlemen:

We have acted as special counsel to InterMune, Inc., a Delaware corporation (the “Company”), in connection with the proposed issuance of up to 8,050,000 shares of common stock, $0.001 par value per share (the “Shares”). The Shares are included in a registration statement on Form S–3 under the Securities Act of 1933, as amended (the “Act”), filed with the Securities and Exchange Commission (the “Commission”) on September 4, 2009 (File No. 333-161758) (as so filed and as amended, the “Registration Statement”), a base prospectus dated September 29, 2009 (the “Base Prospectus”) and a prospectus supplement dated January 20, 2010 (together with the Base Prospectus, the “Prospectus”) and an underwriting agreement dated January 20, 2010 between Goldman, Sachs & Co. and the Company (the “Underwriting Agreement”).

This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement or the Prospectus, other than as expressly stated herein with respect to the issue of the Shares.

As such counsel, we have examined such matters of fact and questions of law as we have considered appropriate for purposes of this letter. With your consent, we have relied upon certificates and other assurances of officers of the Company and others as to factual matters without having independently verified such factual matters. We are opining herein as to General Corporation Law of the State of Delaware (the “DGCL”), and we express no opinion with respect to any other laws.

Subject to the foregoing and the other matters set forth herein, it is our opinion that, as of the date hereof, the issue and sale of the Shares has been duly authorized by all necessary

January 21, 2010

Page 2

corporate action of the Company and, when the Shares shall have been duly registered on the books of the transfer agent and registrar therefor in the name or on behalf of the purchasers, and have been issued by the Company against payment therefor (not less than par value) in the circumstances contemplated by the Underwriting Agreement, the Shares will be validly issued and fully paid and nonassessable. In rendering the foregoing opinion, we have assumed that the Company will comply with all applicable notice requirements regarding uncertificated shares provided in the DGCL.

This opinion is for your benefit in connection with the Registration Statement and the Prospectus and may be relied upon by you and by persons entitled to rely upon it pursuant to the applicable provisions of the Act. We consent to your filing this opinion as an exhibit to the Company’s Form 8-K dated January 21, 2010 and to the reference to our firm in the Prospectus under the heading “Validity of Common Stock.” In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission thereunder.