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PROTEIN DESIGN LABS, INC.
  34801 Campus Drive

Fremont, California 94555

April
1, 2005

VIA
FACSIMILE AND DIRECT TRANSMISSION

Securities
and Exchange Commission

Judiciary Plaza

450 Fifth Street, N.W.

Washington, D.C. 20549

Re: Protein Design Labs, Inc. (the "Company")

Registration Statement on Form S-3

(File No. 333-122760)

Ladies
and Gentleman:

        Pursuant
to Rule 461 under the Securities Act of 1933, as amended, the Company hereby requests that the Commission accelerate the effectiveness of the above-referenced
Registration Statement to 4:00 p.m., Eastern Time, on April 1, 2005, or as soon thereafter as practicable. The Company also hereby requests that a written order verifying the effective
date be sent by express mail.

        The
Company hereby acknowledges that:

•should
the Commission or the Staff, acting pursuant to delegated authority, declare the Registration Statement effective, the Commission is not foreclosed from taking any
action with respect to the Registration Statement;

•the
action of the Commission or the Staff, acting pursuant to delegated authority, in declaring the Registration Statement effective, does not relieve the Company from its
full responsibility for the adequacy and accuracy of the disclosure in the Registration Statement; and

•the
Company may not assert this action as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

        Thank
you for your assistance. If you should have any questions, please call Elizabeth O'Callahan of DLA Piper Rudnick Gray Cary US LLP, counsel to the Company, at
650-833-2271.

Very truly yours,

Protein Design Labs, Inc.

By:

/s/  GLEN SATO       Glen Sato

Senior Vice President and Chief Financial Officer

cc:Albert
Lee, Esq., Securities and Exchange Commission