EXHIBIT 3.1

                          AMENDMENT OF THE BYLAWS OF
                       LIGAND PHARMACEUTICALS INCORPORATED
                                November 8, 2005


                Article II, Section 2, subsection (b) of the Amended and
Restated Bylaws of the Corporation is amended in its entirety to provide as
follows:

                  "(b) At an annual meeting of the stockholders, only such
business shall be conducted as shall have been properly brought before the
meeting. To be properly brought before an annual meeting, business must be: (A)
specified in the notice of meeting (or any supplement thereto) given by or at
the direction of the Board of Directors, (B) otherwise properly brought before
the meeting by or at the direction of the Board of Directors, or (C) otherwise
properly brought before the meeting by a stockholder. For business to be
properly brought before an annual meeting by a stockholder, the stockholder must
have given timely notice thereof in writing to the Secretary of the corporation.
To be timely, a stockholder's notice must be delivered to or mailed and received
at the principal executive offices of the corporation not less than one hundred
twenty (120) calendar days in advance of the date specified in the corporation's
proxy statement released to stockholders in connection with the previous year's
annual meeting of stockholders; provided, however, that in the event that no
annual meeting was held in the previous year or the date of the annual meeting
has been changed by more than thirty (30) days from the date contemplated at the
time of the previous year's proxy statement, notice by the stockholder to be
timely must be so received not later than the close of business on the twentieth
(20th) calendar day following the earlier of the date on which (i) notice of the
date of the annual meeting was mailed to stockholders or (ii) public disclosure
of the date of the meeting was made to stockholders. A stockholder's notice to
the Secretary shall set forth as to each matter the stockholder proposes to
bring before the annual meeting: (i) a brief description of the business desired
to be brought before the annual meeting and the reasons for conducting such
business at the annual meeting, (ii) the name and address, as they appear on the
corporation's books, of the stockholder proposing such business, (iii) the class
and number of shares of the corporation which are beneficially owned by the
stockholder, (iv) any material interest of the stockholder in such business and
(v) any other information that is required to be provided by the stockholder
pursuant to Regulation 14A under the Securities Exchange Act of 1934, as amended
(the "1934 Act"), in his capacity as a proponent to a stockholder proposal.
Notwithstanding the foregoing, in order to include information with respect to a
stockholder proposal in the proxy statement and form of proxy for a
stockholder's meeting, stockholders must provide notice as required by the
regulations promulgated under the 1934 Act. Notwithstanding anything in these
Bylaws to the contrary, no business shall be conducted at any annual meeting
except in accordance with the procedures set forth in this paragraph (b). The
chairman of the annual meeting shall, if the facts warrant, determine and
declare at the meeting that business was not properly brought before the meeting
and in accordance with the provisions of this paragraph (b), and, if he should
so determine, he shall so declare at the meeting that any such business not
properly brought before the meeting shall not be transacted."