<PAGE>   1
           As filed with the Securities and Exchange Commission on July 29, 1997
                                                           Registration No. 333-
================================================================================


                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                             _______________________

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                             _______________________

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

         DELAWARE                                        77-0160744
(State or other jurisdiction                  (IRS Employer Identification No.)
of incorporation or organization)

                            9393 TOWNE CENTRE DRIVE
                          SAN DIEGO, CALIFORNIA 92121
             (Address of principal executive offices)    (Zip Code)
                            ________________________

                     1992 STOCK OPTION/STOCK ISSUANCE PLAN
                       1992 EMPLOYEE STOCK PURCHASE PLAN
                           (Full title of the plans)
                            _______________________

                               DAVID E. ROBINSON
                     PRESIDENT AND CHIEF EXECUTIVE OFFICER
                      LIGAND PHARMACEUTICALS INCORPORATED
              9393 TOWNE CENTRE DRIVE, SAN DIEGO, CALIFORNIA 92121
                    (Name and address of agent for service)
                                 (619) 535-3900
         (Telephone number, including area code, of agent for service)
                            ________________________

This Registration Statement shall become effective immediately upon filing with
the Securities and Exchange Commission, and sales of the registered securities
will thereafter be effected upon option exercises or share issuances effected
under the 1992 Stock Option/Stock Issuance Plan and the 1992 Employee Stock
Purchase Plan.
                           _________________________

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
                                                                Proposed             Proposed
   Title of                                                      Maximum              Maximum
  Securities                               Amount                Offering            Aggregate         Amount of
    to be                                   to be                 Price              Offering         Registration
  Registered                             Registered             per Share              Price              Fee     
  ----------                             ----------             ---------            ---------        ------------
<S>                                    <C>                      <C>               <C>                 <C>
1992 Stock Option/
Stock Issuance Plan

Options to Purchase
Common Stock                                 N/A                   N/A                  N/A                N/A

Common Stock, par value $.001          875,000 shares(1)        $ 11.97(2)        $ 10,473,750(2)      $  3,173.86

1992 Employee Stock
Purchase Plan

Common Stock, par value $.001           40,000 shares(1)        $ 11.97(2)        $    478,800(2)      $    145.09        
-----------------------------        
</TABLE>
                                                                     

(1)      This Registration Statement shall also cover any additional shares of
         Common Stock which become issuable under the 1992 Stock Option/Stock
         Issuance Plan and the 1992 Employee Stock Purchase Plan by reason of
         any stock dividend, stock split, recapitalization or other similar
         transaction effected without the receipt of consideration which
         results in an increase in the number of the Company's outstanding
         shares of Common Stock.


<PAGE>   2


(2)      Calculated solely for purposes of this offering under Rule 457(h) and
         457(c) of the Securities Act of 1933, as amended on the basis of the
         average of the high and low selling prices per share of Common Stock
         of Ligand Pharmaceuticals Incorporated on July 22, 1997, as reported
         by the Nasdaq National Market.

































                                       2.

<PAGE>   3
                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.          INCORPORATION OF DOCUMENTS BY REFERENCE

         Ligand Pharmaceuticals Incorporated (the "Registrant") hereby
incorporates by reference into this Registration Statement the following
documents previously filed with the Securities and Exchange Commission (the
"SEC"):

         (a)              The Registrant's Annual Report on Form 10-K for the
                          fiscal year ended December 31, 1996, filed with the
                          SEC on March 31, 1997;

         (b)              The Registrant's Quarterly Report on Form 10-Q for
                          the fiscal quarter ended March 31, 1997, filed with
                          the SEC on May 15, 1997;

         (c)              The description of the Registrant's Common Stock, par
                          value $.001 per share, contained in the Company's
                          Registration Statement on Form S-3, Registration No.
                          333-12603 filed with the Securities and Exchange
                          Commission on September 25, 1996, as amended on
                          October 22, 1996, and as updated by pertinent
                          information furnished in subsequent reports filed
                          pursuant to Section 13 of the Securities Exchange Act
                          of 1934 (the "1934 Act").

         All reports and definitive proxy or information statements filed
pursuant to Section 13(a), 13(c), 14 or 15(d) of the 1934 Act after the date of
this Registration Statement and prior to the filing of a post-effective
amendment which indicates that all securities offered hereby have been sold or
which deregisters all securities then remaining unsold shall be deemed to be
incorporated by reference into this Registration Statement and to be a part
hereof from the date of filing of such documents.  Any statement contained in a
document incorporated or deemed to be incorporated by reference herein shall be
deemed to be modified or superseded for purposes of this Registration Statement
to the extent that a statement contained herein or in any subsequently filed
document which also is deemed to be incorporated by reference herein modifies
or supersedes such statement.  Any such statement so modified or superseded
shall not be deemed, except as so modified or superseded, to constitute a part
of this Registration Statement.

ITEM 4.          DESCRIPTION OF SECURITIES

                 Not Applicable.

ITEM 5.          INTERESTS OF NAMED EXPERTS AND COUNSEL

                 Not Applicable.

ITEM 6.          INDEMNIFICATION OF DIRECTORS AND OFFICERS

         (a)     Section 145 of the Delaware General Corporation Law permits
indemnification of officers and directors of Ligand under certain conditions
and subject to certain limitations.  Section 145 of the Delaware General
Corporation Law also provides that a corporation has the power to purchase and
maintain insurance on behalf of its officers and directors against any
liability asserted against such person and incurred by him or her in such
capacity, or arising out of his or her status as such, whether or not the
corporation would have the power to indemnify him or her against such liability
under the provisions of Section 145 of the Delaware General Corporation Law.





                                     II-1.
<PAGE>   4
         (b)     Article VII, Section 1 of the Bylaws of Ligand provides that
Ligand shall indemnify its officers, directors, employees and agents to the
full extent permitted by the General Corporation Law of Delaware.  The rights
to indemnity thereunder continue as to a person who has ceased to be a
director, officer, employee or agent and inure to the benefit of the heirs,
executors and administrators of the person.  In addition, expenses incurred by
a director or officer in defending any civil, criminal, administrative or
investigative action, suit or proceeding by reason of the fact that he or she
is or was a director or officer of Ligand (or was serving at Ligand's request
as a director or officer of another corporation) shall be paid by Ligand in
advance of the final disposition of such action, suit or proceeding upon
receipt of an undertaking by or on behalf of such director or officer to repay
such amount if it shall ultimately be determined that he or she is not entitled
to be indemnified by Ligand as authorized by the relevant section of the
Delaware General Corporation Law.

         (c)     As permitted by Section 102(b)(7) of the Delaware General
Corporation Law, Article VI, Section (A)2 of Ligand's Certificate of
Incorporation provides that a director of Ligand shall not be personally liable
for monetary damages or breach of fiduciary duty as a director, except for
liability (i) for any breach of the director's duty of loyalty to Ligand or its
stockholders, (ii) for acts or omissions not in good faith or which involve
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 any improper personal benefit.

         (d)     Article VI, Section (A)1 of Ligand's Certificate of
Incorporation provides that the liability of the directors of Ligand for
monetary damages shall be eliminated to the fullest extent permissible under
California law.  Accordingly, to the extent California law applies, a director
will not be liable for monetary damages for breach of duty to Ligand or its
stockholders in any action brought by or in the right of Ligand.  However, a
director remains liable to the extent required by law (i) for acts or omissions
that involve intentional misconduct or a knowing and culpable violation of law,
(ii) for acts or omissions that a director believes to be contrary to the best
interests of Ligand or its stockholders or that involve the absence of good
faith on the part of the director, (iii) for any transaction from which a
director derived an improper personal benefit, (iv) for acts or omissions that
show a reckless disregard for the director's duty to Ligand or its stockholders
in circumstances in which the director was aware, or should have been aware, in
the ordinary course of performing a director's duties, of a risk of serious
injury to Ligand or its stockholders, (v) for acts or omissions that constitute
an unexcused pattern of inattention that amounts to an abdication of the
director's duty to Ligand or its stockholders, (vi) for any act or omission
occurring prior to the date when the exculpation provision became effective and
(vii) for any act or omission as an officer, notwithstanding that the officer
is also a director or that his or her actions, if negligent or improper, have
been ratified by the directors.  The effect of the provisions in the
Certificate of Incorporation is to eliminate the rights of Ligand and its
stockholders (through stockholders' derivative suits on behalf of Ligand) to
recover monetary damages against a director for breach of duty as a director,
including breaches resulting from negligent behavior in the context of
transactions involving a change of control of Ligand or otherwise, except in
the situations described in clauses (i) through (vii) above.  These provisions
will not alter the liability of directors under federal securities laws.

         (e)     Pursuant to authorization provided under the Certificate of
Incorporation, Ligand has entered into indemnification agreements with each of
its present and certain of its former directors.  Ligand has also entered into
similar agreements with certain of Ligand's executive officers who are not
directors.  Generally, the indemnification agreements attempt to provide the
maximum protection permitted by Delaware and California law as it may be
amended from time to time.  Moreover, the indemnification agreements provide
for certain additional indemnification.  Under such additional indemnification
provisions, however, an individual will not receive indemnification for
judgments, settlements or expenses if he or she is found liable to Ligand
(except to the extent the court determines he or she is fairly and reasonably
entitled to indemnity for expenses), for settlements not approved by Ligand or
for settlements and expenses if the settlement is not approved by the court.
The indemnification agreements provide for Ligand to advance to the individual
any and all reasonable expenses (including legal fees and expenses) incurred in
investigating or defending any such action, suit or proceeding.  In order to
receive an advance of expenses, the individual must submit to Ligand copies of
invoices presented to him or her for such expenses.  Also, the individual must
repay such advances upon a final judicial





                                     II-2.
<PAGE>   5
decision that he or she is not entitled to indemnification.  Ligand's Bylaws
contain a provision of similar effect relating to advancement of expenses to a
director or officer, subject to an undertaking to repay if it is ultimately
determined that indemnification is unavailable.

         (f)     There is directors and officers liability insurance now in
effect which insures directors and officers of the Company.

ITEM 7.          EXEMPTION FROM REGISTRATION CLAIMED

                 Not Applicable.

ITEM 8.          EXHIBITS

      Exhibit Number      Exhibit

             5.1          Opinion and consent of Brobeck, Phleger & Harrison LLP

             23.1         Consent of Brobeck, Phleger & Harrison LLP (contained
                          in Exhibit 5.1)

             23.2         Consent of Ernst & Young LLP, independent auditors

             24.1         Power of Attorney. Reference is made to the signature
                          page of this registration statement

             99.1         1992 Stock Option/Stock Issuance Plan, as amended

             99.2         1992 Employee Stock Purchase Plan, as amended

ITEM 9.          UNDERTAKINGS

         A.      The undersigned Registrant hereby undertakes: (1) to file,
during any period in which offers or sales are being made, a post-effective
amendment to this Registration Statement (i) to include any prospectus required
by Section 10(a)(3) of the 1933 Act, (ii) to reflect in the prospectus any
facts or events arising after the effective date of this Registration Statement
(or the most recent post-effective amendment thereof) which, individually or in
the aggregate, represent a fundamental change in the information set forth in
this Registration Statement and (iii) to include any material information with
respect to the plan of distribution not previously disclosed in this
Registration Statement or any material change to such information in this
Registration Statement; provided, however, that clauses (1)(i) and (1)(ii)
shall not apply if the information required to be included in a post-effective
amendment by those paragraphs is contained in periodic reports filed by the
Registrant pursuant to Section 13 or Section 15(d) of the 1934 Act that are
incorporated by reference into this Registration Statement; (2) that for the
purpose of determining any liability under the 1933 Act, each such
post-effective amendment shall be deemed to be new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof; and
(3) to remove from registration by means of a post-effective amendment any of
the securities being registered which remain unsold at the termination of the
offering.

         B.      The undersigned Registrant hereby undertakes that, for
purposes of determining any liability under the 1933 Act, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
1934 Act that is incorporated by reference into this Registration Statement
shall be deemed to be a new registration statement relating to the securities
offered therein, and the offering of such securities at that time shall be
deemed to be the initial bona fide offering thereof.

         C.      Insofar as indemnification for liabilities arising under the
1933 Act may be permitted to directors, officers, or controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that, in the opinion of the SEC, such indemnification is
against public policy as expressed in the 1933 Act, and is, therefore,
unenforceable.  In the event that a claim for indemnification against such
liabilities (other than the payment by the Registrant of expenses incurred or
paid by a director, officer, or





                                     II-3.

<PAGE>   6

controlling person of the Registrant in the successful defense of any action,
suit or proceeding) is asserted by such director, officer or controlling person
in connection with the securities being registered, the Registrant will, unless
in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the 1933
Act and will be governed by the final adjudication of such issue.
























                                     II-4.

<PAGE>   7
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as
amended, the registrant certifies that it has reasonable grounds to believe
that it meets all of the requirements for filing on Form S-8 and has duly
caused this Registration Statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of San Diego, State of
California, on this 29th day of July, 1997.

                                   LIGAND PHARMACEUTICALS INCORPORATED


                                   By   /s/ David E. Robinson   
                                     ----------------------------------------
                                        David E. Robinson
                                        President and Chief Executive Officer




























                                     II-5.


<PAGE>   8

                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

         That the undersigned officers and directors of Ligand Pharmaceuticals
Incorporated, a Delaware corporation, do hereby constitute and appoint David E.
Robinson and Paul V. Maier, and each of them, the lawful attorneys-in-fact and
agents with full power and authority to do any and all acts and things and to
execute any and all instruments which said attorneys and agents, and either one
of them, determine may be necessary or advisable or required to enable said
corporation to comply with the Securities Act of 1933, as amended, and any
rules or regulations or requirements of the Securities and Exchange Commission
in connection with this registration statement.  Without limiting the
generality of the foregoing power and authority, the powers granted include the
power and authority to sign the names of the undersigned officers and directors
in the capacities indicated below to this registration statement, to any and
all amendments, both pre-effective and post-effective, and supplements to this
registration statement, and to any and all instruments or documents filed as
part of or in conjunction with this registration statement or amendments or
supplements thereof, and each of the undersigned hereby ratifies and confirms
that all said attorneys and agents, or either of them, shall do or cause to be
done by virtue hereof.  This Power of Attorney may be signed in several
counterparts.

         IN WITNESS WHEREOF, each of the undersigned has executed this Power of
Attorney as of the date indicated.

         Pursuant to the requirements of the Securities Act of 1933, as
amended, this registration statement has been signed below by the following
persons in the capacities and on the dates indicated.


<TABLE>
<CAPTION>
Signature                                          Title                                                      Date
---------                                          -----                                                      ----

<S>                                                <C>                                                    <C>
/s/ David E. Robinson                              President, Chief Executive                             July 29, 1997
---------------------------------                  Officer and Director (Principal
David E. Robinson                                  Executive Officer)             
                                                   


/s/ Paul V. Maier                                  Senior Vice President and Chief                        July 29, 1997
---------------------------------                  Financial Officer (Principal     
Paul V. Maier                                      Financial and Accounting Officer)
                                                   


/s/ Henry F. Blissenbach                           Director                                               July 29, 1997
---------------------------------    
Henry F. Blissenbach


/s/ Alexander D. Cross                             Director                                               July 29, 1997
---------------------------------    
Alexander D. Cross


                                                   Director              
---------------------------------    
John Groom


/s/ Irving S. Johnson                              Director                                               July 29, 1997
---------------------------------    
Irving S. Johnson

/s/ Carl C. Peck                                   Director                                               July 29, 1997
---------------------------------    
Carl C. Peck

/s/ William C. Shepard                             Director                                               July 29, 1997
---------------------------------    
William C. Shepherd
</TABLE>





                                     II-6.
<PAGE>   9





                       SECURITIES AND EXCHANGE COMMISSION

                                WASHINGTON, D.C.



                                    EXHIBITS

                                       TO

                                    FORM S-8

                                     UNDER

                             SECURITIES ACT OF 1933


                      LIGAND PHARMACEUTICALS INCORPORATED












<PAGE>   10

                                 EXHIBIT INDEX



Exhibit
Number                            Document
------                            --------
5.1         Opinion and consent of Brobeck, Phleger & Harrison LLP
23.1        Consent of Brobeck, Phleger & Harrison LLP (contained in
            Exhibit 5.1)
23.2        Consent of Ernst & Young LLP, independent auditors
24.1        Power of Attorney.  Reference is made to the
            signature page of this registration statement
99.1        1992 Stock Option/Stock Issuance Plan, as amended
99.2        1992 Employee Stock Purchase Plan, as amended
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 23992}]
{"company-data": {"conformed-name": "LIGAND PHARMACEUTICALS INC", "cik": "0000886163", "assigned-sic": "2834", "irs-number": "770160744", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-32297", "film-number": "97647030"}, "business-address": {"street1": "9393 TOWNE CENTRE DR STE 100", "city": "SAN DIEGO", "state": "CA", "zip": "92121", "phone": "6195353900"}, "mail-address": {"street1": "9393 TOWNE CENTRE DRIVE", "city": "SAN DIEGO", "state": "CA", "zip": "92121"}}
1
           As filed with the Securities and Exchange Commission on July 29, 1997
                                                           Registration No. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                             _______________________

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                             _______________________

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

         DELAWARE                                        77-0160744
(State or other jurisdiction                  (IRS Employer Identification No.)
of incorporation or organization)

                            9393 TOWNE CENTRE DRIVE
                          SAN DIEGO, CALIFORNIA 92121
             (Address of principal executive offices)    (Zip Code)
                            ________________________

                     1992 STOCK OPTION/STOCK ISSUANCE PLAN
                       1992 EMPLOYEE STOCK PURCHASE PLAN
                           (Full title of the plans)
                            _______________________

                               DAVID E. ROBINSON
                     PRESIDENT AND CHIEF EXECUTIVE OFFICER
                      LIGAND PHARMACEUTICALS INCORPORATED
              9393 TOWNE CENTRE DRIVE, SAN DIEGO, CALIFORNIA 92121
                    (Name and address of agent for service)
                                 (619) 535-3900
         (Telephone number, including area code, of agent for service)
                            ________________________

This Registration Statement shall become effective immediately upon filing with
the Securities and Exchange Commission, and sales of the registered securities
will thereafter be effected upon option exercises or share issuances effected
under the 1992 Stock Option/Stock Issuance Plan and the 1992 Employee Stock
Purchase Plan.
                           _________________________

                        CALCULATION OF REGISTRATION FEE
Proposed             Proposed
   Title of                                                      Maximum              Maximum
  Securities                               Amount                Offering            Aggregate         Amount of
    to be                                   to be                 Price              Offering         Registration
  Registered                             Registered             per Share              Price              Fee     
  ----------                             ----------             ---------            ---------        ------------
1992 Stock Option/
Stock Issuance Plan

Options to Purchase
Common Stock                                 N/A                   N/A                  N/A                N/A

Common Stock, par value $.001          875,000 shares(1)        $ 11.97(2)        $ 10,473,750(2)      $  3,173.86

1992 Employee Stock
Purchase Plan

Common Stock, par value $.001           40,000 shares(1)        $ 11.97(2)        $    478,800(2)      $    145.09        
-----------------------------
(1)      This Registration Statement shall also cover any additional shares of
         Common Stock which become issuable under the 1992 Stock Option/Stock
         Issuance Plan and the 1992 Employee Stock Purchase Plan by reason of
         any stock dividend, stock split, recapitalization or other similar
         transaction effected without the receipt of consideration which
         results in an increase in the number of the Company's outstanding
         shares of Common Stock.
2

(2)      Calculated solely for purposes of this offering under Rule 457(h) and
         457(c) of the Securities Act of 1933, as amended on the basis of the
         average of the high and low selling prices per share of Common Stock
         of Ligand Pharmaceuticals Incorporated on July 22, 1997, as reported
         by the Nasdaq National Market.

                                       2.
3
                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.          INCORPORATION OF DOCUMENTS BY REFERENCE

         Ligand Pharmaceuticals Incorporated (the "Registrant") hereby
incorporates by reference into this Registration Statement the following
documents previously filed with the Securities and Exchange Commission (the
"SEC"):

         (a)              The Registrant's Annual Report on Form 10-K for the
                          fiscal year ended December 31, 1996, filed with the
                          SEC on March 31, 1997;

         (b)              The Registrant's Quarterly Report on Form 10-Q for
                          the fiscal quarter ended March 31, 1997, filed with
                          the SEC on May 15, 1997;

         (c)              The description of the Registrant's Common Stock, par
                          value $.001 per share, contained in the Company's
                          Registration Statement on Form S-3, Registration No.
                          333-12603 filed with the Securities and Exchange
                          Commission on September 25, 1996, as amended on
                          October 22, 1996, and as updated by pertinent
                          information furnished in subsequent reports filed
                          pursuant to Section 13 of the Securities Exchange Act
                          of 1934 (the "1934 Act").

         All reports and definitive proxy or information statements filed
pursuant to Section 13(a), 13(c), 14 or 15(d) of the 1934 Act after the date of
this Registration Statement and prior to the filing of a post-effective
amendment which indicates that all securities offered hereby have been sold or
which deregisters all securities then remaining unsold shall be deemed to be
incorporated by reference into this Registration Statement and to be a part
hereof from the date of filing of such documents.  Any statement contained in a
document incorporated or deemed to be incorporated by reference herein shall be
deemed to be modified or superseded for purposes of this Registration Statement
to the extent that a statement contained herein or in any subsequently filed
document which also is deemed to be incorporated by reference herein modifies
or supersedes such statement.  Any such statement so modified or superseded
shall not be deemed, except as so modified or superseded, to constitute a part
of this Registration Statement.

ITEM 4.          DESCRIPTION OF SECURITIES

                 Not Applicable.

ITEM 5.          INTERESTS OF NAMED EXPERTS AND COUNSEL

                 Not Applicable.

ITEM 6.          INDEMNIFICATION OF DIRECTORS AND OFFICERS

         (a)     Section 145 of the Delaware General Corporation Law permits
indemnification of officers and directors of Ligand under certain conditions
and subject to certain limitations.  Section 145 of the Delaware General
Corporation Law also provides that a corporation has the power to purchase and
maintain insurance on behalf of its officers and directors against any
liability asserted against such person and incurred by him or her in such
capacity, or arising out of his or her status as such, whether or not the
corporation would have the power to indemnify him or her against such liability
under the provisions of Section 145 of the Delaware General Corporation Law.

                                     II-1.
4
         (b)     Article VII, Section 1 of the Bylaws of Ligand provides that
Ligand shall indemnify its officers, directors, employees and agents to the
full extent permitted by the General Corporation Law of Delaware.  The rights
to indemnity thereunder continue as to a person who has ceased to be a
director, officer, employee or agent and inure to the benefit of the heirs,
executors and administrators of the person.  In addition, expenses incurred by
a director or officer in defending any civil, criminal, administrative or
investigative action, suit or proceeding by reason of the fact that he or she
is or was a director or officer of Ligand (or was serving at Ligand's request
as a director or officer of another corporation) shall be paid by Ligand in
advance of the final disposition of such action, suit or proceeding upon
receipt of an undertaking by or on behalf of such director or officer to repay
such amount if it shall ultimately be determined that he or she is not entitled
to be indemnified by Ligand as authorized by the relevant section of the
Delaware General Corporation Law.

         (c)     As permitted by Section 102(b)(7) of the Delaware General
Corporation Law, Article VI, Section (A)2 of Ligand's Certificate of
Incorporation provides that a director of Ligand shall not be personally liable
for monetary damages or breach of fiduciary duty as a director, except for
liability (i) for any breach of the director's duty of loyalty to Ligand or its
stockholders, (ii) for acts or omissions not in good faith or which involve
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 any improper personal benefit.

         (d)     Article VI, Section (A)1 of Ligand's Certificate of
Incorporation provides that the liability of the directors of Ligand for
monetary damages shall be eliminated to the fullest extent permissible under
California law.  Accordingly, to the extent California law applies, a director
will not be liable for monetary damages for breach of duty to Ligand or its
stockholders in any action brought by or in the right of Ligand.  However, a
director remains liable to the extent required by law (i) for acts or omissions
that involve intentional misconduct or a knowing and culpable violation of law,
(ii) for acts or omissions that a director believes to be contrary to the best
interests of Ligand or its stockholders or that involve the absence of good
faith on the part of the director, (iii) for any transaction from which a
director derived an improper personal benefit, (iv) for acts or omissions that
show a reckless disregard for the director's duty to Ligand or its stockholders
in circumstances in which the director was aware, or should have been aware, in
the ordinary course of performing a director's duties, of a risk of serious
injury to Ligand or its stockholders, (v) for acts or omissions that constitute
an unexcused pattern of inattention that amounts to an abdication of the
director's duty to Ligand or its stockholders, (vi) for any act or omission
occurring prior to the date when the exculpation provision became effective and
(vii) for any act or omission as an officer, notwithstanding that the officer
is also a director or that his or her actions, if negligent or improper, have
been ratified by the directors.  The effect of the provisions in the
Certificate of Incorporation is to eliminate the rights of Ligand and its
stockholders (through stockholders' derivative suits on behalf of Ligand) to
recover monetary damages against a director for breach of duty as a director,
including breaches resulting from negligent behavior in the context of
transactions involving a change of control of Ligand or otherwise, except in
the situations described in clauses (i) through (vii) above.  These provisions
will not alter the liability of directors under federal securities laws.

         (e)     Pursuant to authorization provided under the Certificate of
Incorporation, Ligand has entered into indemnification agreements with each of
its present and certain of its former directors.  Ligand has also entered into
similar agreements with certain of Ligand's executive officers who are not
directors.  Generally, the indemnification agreements attempt to provide the
maximum protection permitted by Delaware and California law as it may be
amended from time to time.  Moreover, the indemnification agreements provide
for certain additional indemnification.  Under such additional indemnification
provisions, however, an individual will not receive indemnification for
judgments, settlements or expenses if he or she is found liable to Ligand
(except to the extent the court determines he or she is fairly and reasonably
entitled to indemnity for expenses), for settlements not approved by Ligand or
for settlements and expenses if the settlement is not approved by the court.
The indemnification agreements provide for Ligand to advance to the individual
any and all reasonable expenses (including legal fees and expenses) incurred in
investigating or defending any such action, suit or proceeding.  In order to
receive an advance of expenses, the individual must submit to Ligand copies of
invoices presented to him or her for such expenses.  Also, the individual must
repay such advances upon a final judicial

                                     II-2.
5
decision that he or she is not entitled to indemnification.  Ligand's Bylaws
contain a provision of similar effect relating to advancement of expenses to a
director or officer, subject to an undertaking to repay if it is ultimately
determined that indemnification is unavailable.

         (f)     There is directors and officers liability insurance now in
effect which insures directors and officers of the Company.

ITEM 7.          EXEMPTION FROM REGISTRATION CLAIMED

                 Not Applicable.

ITEM 8.          EXHIBITS

      Exhibit Number      Exhibit

             5.1          Opinion and consent of Brobeck, Phleger & Harrison LLP

             23.1         Consent of Brobeck, Phleger & Harrison LLP (contained
                          in Exhibit 5.1)

             23.2         Consent of Ernst & Young LLP, independent auditors

             24.1         Power of Attorney. Reference is made to the signature
                          page of this registration statement

             99.1         1992 Stock Option/Stock Issuance Plan, as amended

             99.2         1992 Employee Stock Purchase Plan, as amended

ITEM 9.          UNDERTAKINGS

         A.      The undersigned Registrant hereby undertakes: (1) to file,
during any period in which offers or sales are being made, a post-effective
amendment to this Registration Statement (i) to include any prospectus required
by Section 10(a)(3) of the 1933 Act, (ii) to reflect in the prospectus any
facts or events arising after the effective date of this Registration Statement
(or the most recent post-effective amendment thereof) which, individually or in
the aggregate, represent a fundamental change in the information set forth in
this Registration Statement and (iii) to include any material information with
respect to the plan of distribution not previously disclosed in this
Registration Statement or any material change to such information in this
Registration Statement; provided, however, that clauses (1)(i) and (1)(ii)
shall not apply if the information required to be included in a post-effective
amendment by those paragraphs is contained in periodic reports filed by the
Registrant pursuant to Section 13 or Section 15(d) of the 1934 Act that are
incorporated by reference into this Registration Statement; (2) that for the
purpose of determining any liability under the 1933 Act, each such
post-effective amendment shall be deemed to be new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof; and
(3) to remove from registration by means of a post-effective amendment any of
the securities being registered which remain unsold at the termination of the
offering.

         B.      The undersigned Registrant hereby undertakes that, for
purposes of determining any liability under the 1933 Act, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
1934 Act that is incorporated by reference into this Registration Statement
shall be deemed to be a new registration statement relating to the securities
offered therein, and the offering of such securities at that time shall be
deemed to be the initial bona fide offering thereof.

         C.      Insofar as indemnification for liabilities arising under the
1933 Act may be permitted to directors, officers, or controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that, in the opinion of the SEC, such indemnification is
against public policy as expressed in the 1933 Act, and is, therefore,
unenforceable.  In the event that a claim for indemnification against such
liabilities (other than the payment by the Registrant of expenses incurred or
paid by a director, officer, or

                                     II-3.
6

controlling person of the Registrant in the successful defense of any action,
suit or proceeding) is asserted by such director, officer or controlling person
in connection with the securities being registered, the Registrant will, unless
in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the 1933
Act and will be governed by the final adjudication of such issue.

                                     II-4.
7
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as
amended, the registrant certifies that it has reasonable grounds to believe
that it meets all of the requirements for filing on Form S-8 and has duly
caused this Registration Statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of San Diego, State of
California, on this 29th day of July, 1997.

                                   LIGAND PHARMACEUTICALS INCORPORATED

                                   By   /s/ David E. Robinson   
                                     ----------------------------------------
                                        David E. Robinson
                                        President and Chief Executive Officer

                                     II-5.
8

                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

         That the undersigned officers and directors of Ligand Pharmaceuticals
Incorporated, a Delaware corporation, do hereby constitute and appoint David E.
Robinson and Paul V. Maier, and each of them, the lawful attorneys-in-fact and
agents with full power and authority to do any and all acts and things and to
execute any and all instruments which said attorneys and agents, and either one
of them, determine may be necessary or advisable or required to enable said
corporation to comply with the Securities Act of 1933, as amended, and any
rules or regulations or requirements of the Securities and Exchange Commission
in connection with this registration statement.  Without limiting the
generality of the foregoing power and authority, the powers granted include the
power and authority to sign the names of the undersigned officers and directors
in the capacities indicated below to this registration statement, to any and
all amendments, both pre-effective and post-effective, and supplements to this
registration statement, and to any and all instruments or documents filed as
part of or in conjunction with this registration statement or amendments or
supplements thereof, and each of the undersigned hereby ratifies and confirms
that all said attorneys and agents, or either of them, shall do or cause to be
done by virtue hereof.  This Power of Attorney may be signed in several
counterparts.

         IN WITNESS WHEREOF, each of the undersigned has executed this Power of
Attorney as of the date indicated.

         Pursuant to the requirements of the Securities Act of 1933, as
amended, this registration statement has been signed below by the following
persons in the capacities and on the dates indicated.
Signature                                          Title                                                      Date
---------                                          -----                                                      ----
/s/ David E. Robinson                              President, Chief Executive                             July 29, 1997
---------------------------------                  Officer and Director (Principal
David E. Robinson                                  Executive Officer)             
                                                   

/s/ Paul V. Maier                                  Senior Vice President and Chief                        July 29, 1997
---------------------------------                  Financial Officer (Principal     
Paul V. Maier                                      Financial and Accounting Officer)
                                                   

/s/ Henry F. Blissenbach                           Director                                               July 29, 1997
---------------------------------    
Henry F. Blissenbach

/s/ Alexander D. Cross                             Director                                               July 29, 1997
---------------------------------    
Alexander D. Cross

                                                   Director              
---------------------------------    
John Groom

/s/ Irving S. Johnson                              Director                                               July 29, 1997
---------------------------------    
Irving S. Johnson

/s/ Carl C. Peck                                   Director                                               July 29, 1997
---------------------------------    
Carl C. Peck

/s/ William C. Shepard                             Director                                               July 29, 1997
---------------------------------    
William C. Shepherd
II-6.
9

                       SECURITIES AND EXCHANGE COMMISSION

                                WASHINGTON, D.C.

                                    EXHIBITS

                                       TO

                                    FORM S-8

                                     UNDER

                             SECURITIES ACT OF 1933

                      LIGAND PHARMACEUTICALS INCORPORATED
10

                                 EXHIBIT INDEX

Exhibit
Number                            Document
------                            --------
5.1         Opinion and consent of Brobeck, Phleger & Harrison LLP
23.1        Consent of Brobeck, Phleger & Harrison LLP (contained in
            Exhibit 5.1)
23.2        Consent of Ernst & Young LLP, independent auditors
24.1        Power of Attorney.  Reference is made to the
            signature page of this registration statement
99.1        1992 Stock Option/Stock Issuance Plan, as amended
99.2        1992 Employee Stock Purchase Plan, as amended