EXHIBIT 3.1

COMPOSITE CERTIFICATE OF INCORPORATION

OF

HALOZYME THERAPEUTICS, INC.

(as amended through May 16, 2013)

FIRST:  The name of the corporation is:

Halozyme Therapeutics, Inc.

SECOND:  The address of its registered office in the State of Delaware is The Corporation Trust Company, 1209 Orange Street, City of Wilmington, County of New Castle. The name of the registered agent at that address is The Corporation Trust Company.

THIRD:  The nature of the business or purposes to be conducted or promoted is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of Delaware.

FOURTH:  The corporation is authorized to issue two classes of stock, to be designated “Common Stock,” with a par value of $0.001 per share, and “Preferred Stock,” with a par value of $0.001 per share. The total number of shares of Common Stock that the corporation shall have authority to issue is 200,000,000, and the total number of shares of Preferred Stock that the corporation shall have authority to issue is 20,000,000.

The corporation's Board of Directors is authorized, subject to any limitations prescribed by law, to provide for the issuance of the shares of Preferred Stock in series, and by filing a certificate pursuant to the applicable law of the state of Delaware, to establish from time to time the number of shares to be included in each such series, and to fix the designation, powers, preferences and rights of the shares of each such series and any qualifications, limitations or restrictions thereof. The number of authorized shares of any class of capital stock of the corporation may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the outstanding Common Stock of the corporation, without the approval of the holders of the Preferred Stock, or of any series thereof, unless the approval of any such holders is required pursuant to the certificate or certificates establishing any series of Preferred Stock.

FIFTH:

A. The business and affairs of the corporation shall be managed by or under the direction of the Board of Directors. In addition to the powers and authority expressly conferred upon them by statute or by this Certificate of Incorporation or the Bylaws of the corporation, the directors are hereby empowered to exercise all such powers and do all such acts and things as may be exercised or done by the corporation. Election of directors need not be by written ballot, unless the Bylaws so provide.

B. Any action required or permitted to be taken by the stockholders of the Corporation must be effected at a duly called annual or special meeting of stockholders of the Corporation and may not be effected by any consent in writing by such stockholders.

SIXTH:  The Board of Directors is expressly empowered to adopt, amend or repeal Bylaws of the Corporation. Any adoption, amendment or repeal of Bylaws of the Corporation by the Board of Directors shall require the approval of a majority of the directors present at any regular or special meeting of the Board of Directors at which a quorum is present. The stockholders shall also have power to adopt, amend or repeal the Bylaws of the Corporation. Any adoption, amendment or repeal of Bylaws of the Corporation by the stockholders shall require, in addition to any vote of the holders of any class or series of stock of the Corporation required by law or by this Certificate of Incorporation, the affirmative vote of the holders of at least a majority of the voting power of all of the then outstanding shares of the capital stock of the Corporation entitled to vote generally in the election of directors, voting together as a single class.

SEVENTH:  A director of the Corporation shall not be personally liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except for liability (i) for any breach of the director's duty of loyalty to the Corporation or its stockholders, (ii) for acts or omissions not in good faith or which involved intentional misconduct or a knowing violation of law, (iii) under Section 174 of the Delaware General Corporation Law, or (iv) for any transaction from which the director derived an improper personal benefit.

If the Delaware General Corporation Law is hereafter amended to authorize the further elimination or limitation of the liability of a director, then the liability of a director of the Corporation shall be eliminated or limited to the fullest extent permitted by the Delaware General Corporation Law, as so amended.

Any repeal or modification of the foregoing provisions of this Article SEVENTH by the stockholders of the Corporation shall not adversely affect any right or protection of a director of the Corporation existing at the time of such repeal or modification.

EIGHTH:  The Corporation reserves the right to amend or repeal any provision contained in this Certificate of Incorporation in the manner prescribed by the laws of the State of Delaware and all rights conferred upon stockholders are granted subject to this reservation.