Mail Stop 3-09

							April 18, 2005


Ronald W. Barrett, Ph.D.
Chief Executive Officer
XenoPort, Inc.
3410 Central Expressway
Santa Clara, CA  95051

Re:	Xenoport, Inc.
	Amendment No. 2 to the Registration Statement on Form S-1
	File No. 333-122156

Dear Dr. Barrett:

      We have reviewed your filing and have the following
comments.
Where indicated, we think you should revise your document in
response
to these comments.  If you disagree, we will consider your
explanation as to why our comment is inapplicable or a revision is
unnecessary.  Please be as detailed as necessary in your
explanation.

      Please understand that the purpose of our review process is
to
assist you in your compliance with the applicable disclosure
requirements and to enhance the overall disclosure in your filing.
We look forward to working with you in these respects.  We welcome
any questions you may have about our comments or on any other
aspect
of our review.  Feel free to call us at the telephone numbers
listed
at the end of this letter.

Form S-1

Management`s Discussion and Analysis - Research and Development
Expenses, Page 39
1. We have reviewed your revisions in response to comment 4 of our
March 18, 2005 letter.  The intent of the comment was to get more
disclosure about the costs that you do not identify by project.
For
the amounts for each period in the line items "other" (within
"clinical development") and "research and preclinical" in the
table,
please disclose the amount by  major functional classification
(e.g.
employee related expenses, third party contract research
organizations and investigative sites, third party manufacturing
organizations, consultants, depreciation and other allocated
expenses). Further you say that you do not allocate your employee
and
infrastructure costs on a project-by- project basis yet you
disclose
that you incur substantial preclinical expenses for third party
contract research organizations and investigative sites and third
party manufacturing organizations.  Please disclose these costs on
a
project-by-project basis.  Finally, for costs that you do not
provide
disclosure on a project-by-project basis, provide other
quantitative
or qualitative disclosure that indicates the amount of those
resources being used by project.

*	*	*

      File a pre-effective amendment in response to these
comments.
Provide a letter keying your responses to the comments.  If you
believe complying with these comments is not appropriate, tell us
why
in your letter.  The response letter should be uploaded to EDGAR,
with the form type label "CORRESP" and linked to the registration
statement file number.  We may have comments after reviewing
revised
materials and your responses.

      Submit your request for acceleration at least two business
days
prior to the requested effective date.

      You may contact Keira Ino at (202) 824-5488 or James
Rosenberg
(202) 942-1803 if you have questions regarding comments on the
financial statements and related matters.  Please contact Song
Brandon at (202) 942-2831 or John Krug at (202) 942-2979 with any
other questions.

								Sincerely,



								Jeffrey Riedler
									Assistant Director


cc:  	Suzanne Sawochka Hooper, Esq.
	Kathryn Walker Hall, Esq.
	Cooley Godward LLP
	Five Palo Alto Square
	3000 El Camino Real
	Palo Alto, CA  94306







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