Via Facsimile and U.S. Mail
Mail Stop 3-9

						April 22, 2005


Mark McDade
Chief Executive Officer
Protein Design Labs, Inc.
38401 Campus Drive
Fremont, California 94555

Re:	Registration Statement on Form S-3
	Filed April 8, 2005
	File No. 333-108701

Dear Mr. McDade:

	This is to advise you that we have performed a limited review
of
the above registration statement, and we have the following
comments.

Pending Confidential Treatment Applications

1. It appears that the Company has two pending requests for
confidential treatment, one filed in April 2003 and the other in
March 2005.  We are currently processing these requests and will
issue comments to you in a separate letter that will be
forthcoming.
Please be advised that we will not be in a position to consider a
request for acceleration of effectiveness of the registration
statement until we resolve all issues concerning the confidential
treatment requests.

Selling Securityholders, pages 65-70

2. We note that the next-to-last row in your table of selling
securityholders is reserved for "All other holders of 2005 Notes.
..
.."  In addition, footnote 4 to the table indicates that
information
concerning other selling securityholders will be set forth in
prospectus supplements from time to time, if and when required.

Although it is permissible to designate a group of unknown persons
as
potential sellers in the manner that you have chosen, please
understand that you may not subsequently complete the
identification
of these sellers by means of a prospectus supplement.  Instead,
each
time you identify additional selling securityholders you must do
so
by post-effective amendment.  The only exception in which a
prospectus supplement may be used to add previously unidentified
selling securityholders is if the new sellers acquired their
securities through a transfer, pledge, donation, etc. from selling
securityholders who themselves were identified in the prospectus
pre-
effectively.

	Accordingly, please supplementally confirm your understanding
of
this requirement and 	revise the disclosure in the prospectus
as
necessary to make this clear.

*	*	*

      As appropriate, please amend your registration statement in
response to these comments.  You may wish to provide us with
marked
copies of the amendment to expedite our review.  Please furnish a
cover letter with your amendment that keys your responses to our
comment and provides any requested supplemental information.
Detailed cover letters greatly facilitate our review.  Please
understand that we may have additional comments after reviewing
your
amendment and responses to our comments.

      We urge all persons who are responsible for the accuracy and
adequacy of the disclosure in the filings reviewed by the staff to
be
certain that they have provided all information investors require
for
an informed decision.  Since the company and its management are in
possession of all facts relating to a company`s disclosure, they
are
responsible for the accuracy and adequacy of the disclosures they
have made.

	Notwithstanding our comments, in the event the company
requests
acceleration of the effective date of the pending registration
statement, it should furnish a letter, at the time of such
request,
acknowledging that:

* should the Commission or the staff, acting pursuant to delegated
authority, declare the filing effective, it does not foreclose the
Commission from taking any action with respect to the filing;

* the action of the Commission or the staff, acting pursuant to
delegated authority, in declaring the filing effective, does not
relieve the company from its full responsibility for the adequacy
and
accuracy of the disclosure in the filing; 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.

	In addition, please be advised that the Division of
Enforcement
has access to all information you provide to the staff of the
Division of Corporation Finance in connection with our review of
your
filing or in response to our comments on your filing.

	We will consider a written request for acceleration of the
effective date of the registration statement as a confirmation of
the
fact that those requesting acceleration are aware of their
respective
responsibilities under the Securities Act of 1933 and the
Securities
Exchange Act of 1934 as they relate to the proposed public
offering
of the securities specified in the above registration statement.
We
will act on the request and, pursuant to delegated authority,
grant
acceleration of the effective date.

	Please contact Daniel Greenspan at (202) 942-2974 or me at
(202)
942-1840 with any questions.

							Sincerely,



							Jeffrey P. Riedler
							Assistant Director

cc:	J. Howard Clowes, Esq.
	DLA Piper Rudnick Gray Cary US LLP
	153 Townsend Street, Suite 800
	San Francisco, California 94107

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Protein Design Labs, Inc.
April 22, 2005
Page 1