UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): December 17, 2010

OREXIGEN THERAPEUTICS, INC.

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code: (858) 875-8600

(Former Name or Former Address, if Changed Since Last Report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Beginning on December 17, 2010, representatives of Orexigen Therapeutics, Inc. (the “Company” or “Orexigen”) will be conducting meetings with investors, analysts and others. During these meetings, the Company will present the slides attached as Exhibit 99.1 to this report, which is incorporated herein by reference.

The information in this report, including Exhibits 99.1, is being furnished pursuant to Item 7.01 and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, and it shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or under the Exchange Act, whether made before or after the date hereof, except as expressly set forth by specific reference in such filing to this item of this report.

* * *

By filing this report and furnishing this information, the Company makes no admission as to the materiality of any information in this report. The information contained in this report is intended to be considered in the context of the Company’s filings with the SEC and other public announcements that the Company makes, by press release or otherwise, from time to time. The Company undertakes no duty or obligation to publicly update or revise the information contained in this report, although it may do so from time to time as its management believes is appropriate. Any such updating may be made through the filing of other reports or documents with the SEC, through press releases or through other public disclosure.

Orexigen cautions you that statements included in this report, including Exhibit 99.1, that are not a description of historical facts are forward-looking statements. These forward-looking statements include statements regarding the potential for, and timing of, approval of the Contrave^® New Drug Application (“NDA”) and an NDA submission for Empatic^™; the efficacy and safety of Contrave and Empatic; Orexigen’s belief that Contrave and Empatic may be important and effective therapeutic options in the treatment of obesity; the potential for, timing of, cost and design of a post-approval study to evaluate safety risks of Contrave; the potential milestone and royalty payments under the collaboration agreement with Takeda Pharmaceutical Company Limited; the potential strength of Orexigen’s market entry with Contrave, if approved; and Orexigen’s plans to commence strategic collaboration and/or co-promotion discussions with respect to Empatic and outside of the United States, Contrave. The inclusion of forward-looking statements should not be regarded as a representation by Orexigen that any of its plans will be achieved. Actual results may differ from those set forth in this report due to the risk and uncertainties inherent in the Orexigen business, including, without limitation: the potential for the U.S. Food and Drug Administration (“FDA”) to delay the scheduled Prescription Drug User Fee Act action date of January 31, 2011 due to the FDA’s internal resource constraints or other reasons; the uncertainty of the FDA approval process and other regulatory requirements; the uncertainty of the process with the FDA to agree on and finalize a design for a post-approval study to evaluate safety risks of Contrave; the FDA may not agree with Orexigen’s interpretation of efficacy and safety results; the FDA may require Orexigen to complete additional clinical, non-clinical or other requirements prior to the approval of the Contrave NDA or the submission of an NDA for Empatic; the therapeutic and commercial value of Contrave and Empatic; reliance on third parties to assist with the development of Contrave and Empatic; the potential for adverse safety findings relating to Contrave or Empatic to delay or prevent regulatory approval or commercialization; Orexigen’s ability to enter into additional collaboration or co-promotion arrangements; and other risks described in Orexigen’s filings with the Securities and Exchange Commission. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement and Orexigen undertakes no obligation to revise or update this report to reflect events or circumstances after the date hereof. This caution is made under the safe harbor provisions of Section 21E of the Securities Exchange Act of 1934.

(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.

EXHIBIT INDEX