Exhibit 5(a)

                                [L&W Letterhead]

                                February 1, 1999




Algos Pharmaceutical Corporation
1333 Campus Parkway
Neptune, New Jersey 07753

         Re: Registration Statement on Form S-8 with respect to 800,000
             shares of Common Stock, par value $.01 per share

Ladies and Gentlemen:

          In connection with the preparation and filing by Algos Pharmaceutical
Corporation (the "Company") with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), of a
Registration Statement on Form S-8 (the "Registration Statement") relating to
the issuance by the Company of 800,000 shares of the Company's Common Stock, par
value $.01 per share (the "Shares"), pursuant to the Algos Pharmaceutical
Corporation 1996 Stock Option Plan (the "Plan"), you have requested our opinion
with respect to the matters set forth below.

          In our capacity as your counsel in connection with such registration,
we are familiar with the proceedings taken and proposed to be taken by the
Company in connection with the authorization, issuance and sale of the Shares,
and for the purposes of this opinion, have assumed such proceedings will be
timely completed in the manner presently proposed. In addition, we have made
such legal and factual examinations and inquires, including an examination of
originals or copies certified or otherwise identified to our satisfaction of
such documents, corporate records and instruments, as we have deemed necessary
or appropriate for purposes of this opinion.

          In our examination, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals, and the
conformity to authentic original documents of all documents submitted to us as
copies.

          We are opining herein as to the effect on the subject transaction only
of the internal laws of the State of New York and the General Corporation Law of
the State of Delaware, and we express no opinion with respect to the
applicability thereto, or the effect thereon, of the laws of any other
jurisdiction or, in the case of Delaware, any other laws, or as to any matters
of municipal law or the laws of any local agency within any state.

          Subject to the foregoing, it is our opinion that the Shares have been
duly authorized and, when issued and sold upon exercise of the options for such
Shares and payment



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of the exercise price therefor as contemplated by the Plan will be validly
issued, fully paid and nonassessable.

          We consent to your filing this opinion as an exhibit to the
Registration Statement.

                                   Very truly yours,

                                   /s/ Latham & Watkins







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