Exhibit 3.1

FOURTH AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

OF

PROGENICS PHARMACEUTICALS, INC.

FIRST: The name of the Corporation (the “Corporation”) is

Progenics Pharmaceuticals, Inc.

SECOND: The registered office of the Corporation in the State of Delaware is located at 251 Little Falls Drive, Wilmington, DE 19808, and County of New Castle. The name of its registered agent in the State of Delaware at such address is Corporation Service Company.

THIRD: The purpose of the Corporation is to engage, directly or indirectly, in any lawful act or activity for which corporations may be organized under the General Corporation Law of the State of Delaware (the “DGCL”).

FOURTH: The total authorized capital stock of the Corporation shall be 1,000 shares of common stock, $0.01 par value per share.

FIFTH: The Corporation is to have perpetual existence.

SIXTH: The business of the Corporation shall be managed under the direction of the Board of Directors of the Corporation (the “Board of Directors”) except as otherwise provided by applicable law. The number of directors of the Corporation shall be fixed from time to time by, or in the manner provided in, the By-Laws of the Corporation (the “By-Laws”). Election of directors need not be by written ballot unless the By-Laws shall so provide.

SEVENTH: The Board of Directors may make, alter or repeal the By-Laws except as otherwise provided in the By-Laws adopted by the Corporation’s stockholders.

EIGHTH: The personal liability of the directors of the Corporation is hereby eliminated to the fullest extent permitted by paragraph (7) of subsection (b) of §102 of the General Corporation Law of the State of Delaware, as the same may be amended and supplemented.

NINTH: The Corporation shall, to the fullest extent permitted by Section 145 of the General Corporation Law of the State of Delaware, as amended from time to time, indemnify all persons whom it may indemnify pursuant thereto.

TENTH: The Corporation reserves the right to amend, alter, change or repeal any provision contained in this Certificate of Incorporation in the manner now or hereafter prescribed by statute, and all rights conferred herein upon the Corporation’s stockholders, directors and officers are granted subject to this reservation.