EXHIBIT 10.283

                                LOCK-UP AGREEMENT

This agreement, effective as of January ___, 2005, is made by and between LIGAND
PHARMACEUTICALS INCORPORATED ("Ligand" or the "Company") and each of the
undersigned individuals. When executed, this document shall evidence separate
agreements between the Company and each of the undersigned.

In connection with the proposed option acceleration approved by the Compensation
Committee of the Board of Directors on January 20, 2005 subject to certain
contingencies, each of the undersigned hereby agrees with the Company as
follows:

Upon any acceleration pursuant to the above authorization:

      1.    Accelerated options may be exercised any time after the acceleration
            date, under the terms of the existing Stock Option Agreements and
            Notices of Option Grant;

      2.    Provided however, that any shares acquired pursuant to an
            accelerated option may not be sold, transferred or otherwise
            disposed of prior to the date those shares would have vested under
            the option's original vesting schedule (the "Lock-up") . For the
            avoidance of doubt, the "original vesting schedule" includes any
            accelerated vesting other than that authorized on January 20, 2005
            that may occur pursuant to the terms of the option and/or the terms
            of executive severance or other agreements between the Company and
            an undersigned. It is the intent of the parties that the undersigned
            shall have the full benefit of any other acceleration that may
            occur.

            Exceptions:

                  a.    the Lock-up would not apply to an undersigned after the
                        effective date of his/her resignation, retirement or
                        other termination of employment;

                  b.    the Lock-up would not apply to an undersigned to the
                        extent of shares sold by him/her in order to pay
                        withholding taxes due on the exercise of options subject
                        to the Lock-up.

For the avoidance of doubt, nothing herein shall be construed as a modification
of the Company's Insider Trading Policy, and such Policy shall continue to apply
notwithstanding the above.

This is the entire agreement between the parties on the subject matter hereof
and merges all prior understandings. No amendment to this Agreement shall be
effective unless reduced to writing and signed by Ligand and the relevant
individual(s).

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   ACCEPTED & AGREED:
   Ligand Pharmaceuticals Incorporated
   By:

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   Signature

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   Title


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