Consent of Independent Registered Public Accounting Firm
to the reference to our firm under the caption "Experts" and to the
use of our report dated February 14, 2007 in Amendment No. 2 to
the Registration Statement (Form S-1 No. 333-139496) and the related Prospectus of Orexigen Therapeutics, Inc. for
the registration of shares of its common stock.
/s/ Ernst & Young LLP
February 14, 2007