UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   FORM 8-A/A

                FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                     PURSUANT TO SECTION 12(B) OR (G) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                       LIGAND PHARMACEUTICALS INCORPORATED
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             (Exact name of registrant as specified in its charter)

              DELAWARE                                77-0160744
(State of incorporation or organization)    (I.R.S. Employer Identification No.)

    10275 SCIENCE CENTER DRIVE,                         92121
        SAN DIEGO, CALIFORNIA
(Address of principal executive offices)              (Zip Code)


Securities to be registered pursuant to Section 12(b) of the Act:



         Title of each class                Name of each exchange on which
           to be registered                 each class is to be registered
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            Not applicable                         Not applicable
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If this form relates to the registration of a class of securities pursuant to
Section 12(b) of the Exchange Act and is effective pursuant to General
Instruction A.(c), check the following box. |_|

If this form relates to the registration of a class of securities pursuant to
Section 12(g) of the Exchange Act and is effective pursuant to General
Instruction A.(d), check the following box. |X|

Securities Act registration statement file number to which this form relates:

Securities to be registered pursuant to Section 12(g) of the Act:


                         PREFERRED SHARE PURCHASE RIGHTS
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                                (Title of class)




                 INFORMATION REQUIRED IN REGISTRATION STATEMENT

     Ligand Pharmaceuticals Incorporated (the "Registrant") hereby amends and
supplements certain information in Items 1 and 2 of its Registration Statement
on Form 8-A filed with the Securities and Exchange Commission (the "Commission")
on September 30, 1996, as amended by Amendments No. 1 and No. 2 to Form 8-A/A
filed with the Commission on November 10, 1998 and December 24, 1998,
respectively. In accordance with Rule 12b-15 of the Securities and Exchange Act
of 1934, as amended, the complete text of Items 1 and 2, as amended by this Form
8-A/A, is set forth below

ITEM I. DESCRIPTION OF REGISTRANT'S SECURITIES TO BE REGISTERED.

     Effective as of September 13, 1996, pursuant to a Preferred Shares Rights
Agreement (the "Original Rights Agreement") between Ligand Pharmaceuticals
Incorporated (the "Company") and Wells Fargo Bank N.A., as the Company's
original Rights Agent, the Company's Board of Directors declared a dividend of
one right (a "Right") to purchase one one-thousandth share of the Company's
Series A Participating Preferred Stock ("Series A Preferred") for each
outstanding share of Common Stock, par value $0.001 per share ("Common Shares"),
of the Company. The dividend is payable on September 30, 1996 (the "Record
Date") to stockholders of record as of the close of business on that date. Each
Right entitles the registered holder to purchase from the Company one
one-thousandth of a share of Series A Preferred at an exercise price of $100
(the "Purchase Price"), subject to adjustment in the event the Company declares
a dividend on the Common Stock payable in Common Stock, subdivides the number of
outstanding shares of Common Stock into a larger number of such shares or
combines the number of outstanding shares of Common Stock into a smaller number
of such shares, among other circumstances. In addition, under certain
circumstances described more fully herein, the Rights may become exercisable for
a number of Common Shares having a value equal to two times the Purchase Price
and/or Common Stock of certain acquiring companies having a value equal to two
times the Purchase Price.

     On March 20, 2004, the Company amended and restated in its entirety the
Original Rights Agreement in order to incorporate certain previous amendments to
the Original Rights Agreement and eliminate certain other amendments to the
Original Rights Agreement providing for specific exceptions to the definitions
of Acquiring Person and Distribution Date for former Company stockholders, Elan
Corporation, plc and its affiliates. The Company's Board of Directors determined
that these exceptions were no longer necessary as a result of Elan and its
affiliates ceasing to be Company stockholders. The Company evidenced its
amendment and restatement of the Original Rights Agreement by entering into an
Amended and Restated Preferred Shares Rights Agreement with Mellon Investor
Services LLC (as the successor to ChaseMellon Shareholder Services, L.L.C., the
successor to and acquirer of Wells Fargo Bank, N.A, the original agent for the
Company), as Rights Agent (the "Rights Agreement").

     The following summary of the principal terms of the Rights Agreement is a
general description only and is subject to the detailed terms and conditions of
the Rights Agreement. A copy of the Rights Agreement is attached as Exhibit 4.1
to this Registration Statement and is incorporated herein by reference;
capitalized terms used but not otherwise defined herein shall have the meanings
ascribed to them in the Rights Agreement.

     CERTAIN ANTI-TAKEOVER EFFECTS

     The Rights approved by the Board are designed to protect and maximize the
value of the outstanding equity interests in the Company in the event of an
unsolicited attempt by an acquiror to take over the Company, in a manner or on
terms not approved by the Board of Directors. Takeover attempts frequently
include coercive tactics to deprive the Company's Board of Directors and its
stockholders of any real opportunity to determine the destiny of the Company.

     The Rights have been declared by the Board in order to deter such tactics,
including a gradual accumulation in the open market of a 10% or greater position
to be followed by a merger or a partial or two-tier tender offer that does not
treat all stockholders equally. These tactics can operate to unfairly pressure
stockholders, force them out of their investment and deprive them of the full
value of their shares.

     The Rights are not intended to prevent a takeover of the Company and will
not do so. The Rights may be redeemed by the Company at $.01 per Right within
ten days (or on such later date as may be determined by a majority of the Board
of Directors, excluding directors affiliated with an Acquiring Person) after the
accumulation of 10% or more of the Company's shares by a single acquiror or
group. Accordingly, the Rights should not interfere with any merger or business
combination approved by the Board of Directors.


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However, the Rights may have the effect of rendering more difficult or
discouraging an acquisition of the Company deemed undesirable by the Board of
Directors. The Rights may cause substantial dilution to a person or group that
attempts to acquire the Company on terms or in a manner not approved by the
Company's Board of Directors, except pursuant to an offer conditioned upon the
negation, purchase or redemption of the Rights. As a result, while the Rights
may provide the Board with leverage to obtain a higher price from a potential
acquiror, they may also prevent or deter offers not approved by the Board, and
therefore deprive stockholders, without providing them with the opportunity to
vote thereon, of the benefits of offers which may be at a higher price than the
current market price of the Company's Common Stock. In addition, assuming an
active trading market in the Rights themselves does not develop, stockholders
with lesser financial means might not be able to take full economic advantage of
the Rights. Further, the implementation of a rights plan may heighten the
susceptibility of the Company to greenmail by stockholders who threaten to
acquire a sufficient equity position to pass the Rights' triggering threshold,
although the Board can respond to any such action by redeeming the Rights at
$.01 per Right.

     Issuance of the Rights does not in any way weaken the financial strength of
the Company or interfere with its business plans. The issuance of the Rights
themselves has no dilutive effect, will not affect reported earnings per share,
should not be taxable to the Company or to its stockholders, and will not change
the way in which the Company's shares are presently traded. The Company's Board
of Directors believes that the Rights represent a sound and reasonable means of
addressing the complex issues of corporate policy created by the current
takeover environment.

RIGHTS EVIDENCED BY COMMON SHARE CERTIFICATES

     The Rights will not be exercisable until the Distribution Date (defined
below). Prior to the Distribution Date, certificates for the Rights ("Rights
Certificates") will not be sent to stockholders and the Rights will attach to
and trade only together with the Common Shares. Accordingly, Common Share
certificates outstanding on the Record Date will evidence the Rights related
thereto, and Common Share certificates issued after the Record Date but prior to
the Distribution Date will contain a notation incorporating the Rights Agreement
by reference. Until the Distribution Date (or earlier redemption or expiration
of the Rights), the surrender or transfer of any certificates for Common Shares,
even without notation or a copy of the Summary of Rights being attached thereto
(but as to certificates representing Common Shares issued after the Record Date,
only if they bear the legend required by the Rights Agreement), will also
constitute the transfer of the Rights associated with the Common Shares
represented by such certificate.

DISTRIBUTION DATE

     The Rights will separate from the Common Shares, Rights Certificates will
be issued and the Rights will become exercisable upon the earlier of: (i) 10
days (or such later date as may be determined by the Company's Board of
Directors) following a public announcement that a person or group of affiliated
or associated persons (an "Acquiring Person") has acquired, or obtained the
right to acquire, beneficial ownership of 10% or more of the outstanding Common
Shares, or (ii) 10 days (or such later date as may be determined by the
Company's Board of Directors) following the commencement of, or announcement of
an intention to make, a tender offer or exchange offer the consummation of which
would result in the beneficial ownership by a person or group of 10% or more of
the outstanding Common Shares. The earlier of such dates is referred to as the
"Distribution Date."

ISSUANCE OF RIGHTS CERTIFICATES; EXPIRATION OF RIGHTS

     As soon as practicable following the Distribution Date, separate Rights
Certificates will be mailed to holders of record of the Common Shares as of the
close of business on the Distribution Date and such separate Rights Certificates
alone will evidence the Rights from and after the Distribution Date. All Common
Shares issued prior to the Distribution Date will be issued with Rights. Common
Shares issued after the Distribution Date may be issued with Rights if such
shares are issued (i) upon the conversion of outstanding convertible debentures
or any other convertible securities issued after adoption of the Rights
Agreement or (ii) pursuant to the exercise of stock options or under employee
benefit plans or arrangements unless such issuance would result in (or create a
risk that) such options, plans or arrangements would not qualify for otherwise
available special tax treatment. Except as otherwise determined by the Board of
Directors, no other Common Shares issued after the Distribution Date will be
issued with Rights. The Rights will expire on the earliest of (i) September 13,
2006 (the "Final Expiration Date") or (ii) redemption or exchange of the Rights
as described below.


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INITIAL EXERCISE OF THE RIGHTS

     Following the Distribution Date, and until one of the further events
described below, holders of the Rights will be entitled to receive, upon
exercise and the payment of $100 per Right, one one-thousandth share of the
Series A Preferred, subject to adjustment in the event the Company declares a
dividend on the Common Shares payable in Common Shares, subdivides the number of
outstanding shares of Common Shares into a larger number of such shares or
combines the number of outstanding shares of Common Shares into a smaller number
of such shares, among other circumstances. In addition, under certain
circumstances described more fully herein, the Rights may become exercisable for
Common Shares having a value equal to two times the Purchase Price and/or Common
Stock of certain acquiring companies having a value equal to two times the
Purchase Price.

RIGHT TO BUY COMPANY COMMON SHARES

     Unless the Rights are earlier redeemed, in the event that an Acquiring
Person becomes the beneficial owner of 10% or more of the Company's Common
Shares then outstanding, then proper provision will be made so that each holder
of a Right which has not theretofore been exercised (other than Rights
beneficially owned by the Acquiring Person, which will thereafter be void) will
thereafter have the right to receive, upon exercise and payment of the Purchase
Price, Common Shares having a value equal to two times the Purchase Price. For
example, if the market price of Common Shares on the Share Acquisition Date (as
defined below) was $50.00, a person holding one Right could purchase 4 Common
Shares upon exercise of such Right ($100/25.00), whereas he could only purchase
2 Common Shares ($100/50.00) in the absence of such Rights. Rights are not
exercisable following the occurrence of an event as described above until such
time as the Rights are no longer redeemable by the Company as set forth below.

     In the event that the Company does not have sufficient Common Shares
available for all Rights to be exercised, or the Board decides that it is
necessary and not contrary to the interests of Rights holders to do so, the
Company may instead substitute cash, assets or other securities for the Common
Shares for which the Rights would have been exercisable under this provision.

RIGHT TO BUY ACQUIRING COMPANY STOCK

     Similarly, unless the Rights are earlier redeemed, in the event that, after
the Share Acquisition Date, (i) the Company is acquired in a merger or other
business combination transaction, or (ii) 50% or more of the Company's
consolidated assets or earning power are sold (other than in transactions in the
ordinary course of business) (either of which event is referred to herein as an
"Acquisition"), proper provision must be made so that each holder of a Right
which has not theretofore been exercised (other than Rights beneficially owned
by the Acquiring Person, which will thereafter be void) will thereafter have the
right to receive, upon exercise, shares of Common Stock of the acquiring company
having a value equal to two times the Purchase Price. So if for example the
market price of the acquiror's stock on the date of the Acquisition were $25.00,
a person holding one Right could purchase 8 shares of the acquiror's Common
Stock upon exercise of such Right ($100/$12.50), whereas he could only purchase
4 shares of acquiror's Common Stock ($100/$25.00) in the absence of such Rights.

EXCHANGE PROVISION

     At any time after the acquisition by an Acquiring Person of 10% or more of
the Company's outstanding Common Shares and prior to the acquisition by such
Acquiring Person of 50% or more of the Company's outstanding Common Shares, the
Board of Directors of the Company, following the approval of a majority of the
Board of Directors, may exchange the Rights (other than Rights owned by the
Acquiring Person), in whole or in part, at an exchange ratio of one Common Share
per Right.

REDEMPTION

     At any time on or prior to the close of business on the earlier of (i) the
10th day following the acquisition by an Acquiring Person (the "Share
Acquisition Date") or such later date as may be determined by the Company's
Board of Directors and publicly announced by the Company, or (ii) the Final
Expiration Date of the Rights, the Company may redeem the Rights in whole, but
not in part, at a price of $.01 per Right.


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ADJUSTMENTS TO PREVENT DILUTION

     The Purchase Price payable, the number of Rights and the number of Series A
Preferred or Common Shares or other securities or property issuable upon
exercise of the Rights are subject to adjustment from time to time in connection
with the dilutive issuances by the Company as set forth in the Rights Agreement.
With certain exceptions, no adjustment in the Purchase Price will be required
until cumulative adjustments require an adjustment of at least 1% in such
Purchase Price.

CASH PAID INSTEAD OF ISSUING FRACTIONAL SHARES

     No fractional portion less than integral multiples of one one-thousandth of
a Preferred Share will be issued upon exercise of a Right and in lieu thereof,
an adjustment in cash will be made based on the market price of the Common
Shares on the last trading date prior to the date of exercise.

NO STOCKHOLDERS' RIGHTS PRIOR TO EXERCISE

     Until a Right is exercised, the holder thereof, as such, will have no
rights as a stockholder of the Company (other than any rights resulting from
such holder's ownership of Common Shares), including, without limitation, the
right to vote or to receive dividends.

AMENDMENT OF RIGHTS AGREEMENT

     The provisions of the Rights Agreement may be supplemented or amended by
the Board of Directors in any manner prior to the close of business on the
Distribution Date without the approval of Rights holders. After the Distribution
Date, the provisions of the Rights Agreement may be amended by the Board in
order to cure any ambiguity, defect or inconsistency, to make changes which do
not adversely affect the interests of holders of Rights (excluding the interests
of any Acquiring Person), or to shorten or lengthen any time period under the
Rights Agreement; provided, however, that no amendment to adjust the time period
governing redemption shall be made at such time as the Rights are not
redeemable.

RIGHTS AND PREFERENCES OF THE SERIES A PREFERRED


     Series A Preferred purchasable upon exercise of the Rights will not be
redeemable. Each share of Series A Preferred will be entitled to an aggregate
dividend of 1,000 times the dividend declared per Common Share. In the event of
liquidation, the holders of the Series A Preferred will be entitled to a minimum
preferential liquidation payment equal to $1,000 per share. Each share of Series
A Preferred will have 1,000 votes, voting together with the Common Shares. In
the event of any merger, consolidation or other transaction in which the Common
Shares are changed or exchanged, each share of Series A Preferred will be
entitled to receive 1,000 times the amount received per Common Share. These
rights are protected by customary anti-dilution provisions.

     Because of the nature of the dividend, liquidation and voting rights of the
shares of Series A Preferred, the value of the one one-thousandth interest in a
share of Series A Preferred purchasable upon exercise of each Right should
approximate the value of one Common Share.

ITEM 2. EXHIBITS.

The following exhibits are filed as a part of this registration statement:

4.1  Amended and Restated Preferred Shares Rights Agreement dated as of March
     22, 2004 which includes as Exhibit A the form of Rights Certificate and as
     Exhibit B the Summary of Rights. Pursuant to the Amended and Restated
     Preferred Shares Rights Agreement, printed Rights Certificates will not be
     mailed until after a Distribution Date (as defined in the Amended and
     Restated Preferred Shares Rights Agreement).


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                                    SIGNATURE

    Pursuant to the requirements of Section 12 of the Securities Exchange Act of
1934, the Registrant has duly caused this registration statement to be signed on
its behalf by the undersigned, thereto duly authorized.

Date:  April 6, 2004              LIGAND PHARMACEUTICALS INCORPORATED

                               By:/S/ PAUL V. MAIER
                                  ------------------------------------------
                                  Paul V. Maier
                                  Senior Vice President, Chief Financial Officer












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                                  EXHIBIT INDEX

EXHIBIT

4.1      Amended and Restated Preferred Shares Rights Agreement dated as of
March 22, 2004 which includes as Exhibit A the form of Rights Certificate and
as Exhibit B the Summary of Rights. Pursuant to the Amended and Restated
Preferred Shares Rights Agreement, printed Rights Certificates will not be
mailed until after a Distribution Date (as defined in the Amended and Restated
Preferred Shares Rights Agreement).















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