SecProbe.io

Mail Stop 4720
May 18, 2009
 Tod Woolf Chief Executive Officer RXi Pharmaceuticals Corporation 60 Prescott Street Worcester, MA 01605
Re: RXi Pharmaceuticals Corporation
  Registration Statement on Form S-3
Filed May 4, 2009
  File No. 333-158968

Dear Mr. Woolf:

We have limited our review of your filing to those issues we have addressed in
the comments below.  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 revisi on is unnecessary.  Please be as detailed as
necessary in your explanation.

Please understand that the purpose of our re view 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 any other aspect of our review.  Feel free to call us at the telephone numbers listed at the end of this letter.

General

1. We note that you have filed this registrati on statement in reliance on the eligibility
requirements of General Instruction I.B.6 of Form S-3.  General Instruction I.B.6
of Form S-3 requires in part  that the aggregate market value of securities sold by
or on behalf of the registrant pursuant to  Instruction I.B.6 dur ing the period of 12
calendar months immediately prior to, and including, the sale is no more than one-third of the aggregate market va lue of the voting and non-voting common
equity held by non-affiliates  of the registrant.  We further note your disclosure
that, prior to the filing of this registra tion statement, you explored the possibility
of conducting a private placement of co mmon stock with certain prospective
investors but then terminated all offeri ng activity related to the proposed private
placement on April 29, 2009.  Accordingly, we must consider whether the shares

Tod Woolf
RXi Pharmaceuticals Corporation
May 18, 2009 Page 2
offered pursuant to the abandoned private placement must be integrated with the shares offered pursuant to this registra tion statement when determining whether
the size of the offering meets the eligibil ity requirements of General Instruction
I.B.6 of Form S-3.  Rule 155 of th e Securities Act of 1933 provides a non-
exclusive safe harbor with  respect to integration of  abandoned offerings.  Rule
155 states in relevant part that a priv ate offering of securities will not be
considered part of an offering for whic h the issuer later files a registration
statement if, among other things, the issuer does not file the re gistration statement
until at least 30 calendar days after the te rmination of all offering activity in the
private offering, unless securi ties offered in the private offering were only offered
to accredited investors (as that term is defined in Rule 501(a)) or persons who
satisfy the knowledge and e xperience standard of Rule 506(b)(2).  We note that
you have filed this regist ration statement less than 30 calendar days after the
abandonment of your proposed private placem ent.  Accordingly, please reduce the
size of the offering, withdraw the registra tion statement or provide us with an
analysis supporting your determination th at the private placement should not be
integrated with this registration statem ent for purposes of determining that the
number of shares offered meets the eligib ility requirements of General Instruction
I.B.6 of Form S-3.

* * *

As appropriate, please amend your regist ration 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 cove r letter with your amendment that keys your
responses to our comments and provides any requested information.  Detailed cover
letters greatly facilitate our review.  Please understand that we may have additional comments after reviewing your amendmen t and responses to our comments.
We urge all persons who are responsible for the accuracy and adequacy of the
disclosure in the filing to be certain that the filing includes all in formation required under
the Securities Act of 1933 and that they have  provided all information investors require
for an informed investment 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 even t 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 purs uant to delegated authority, declare the
filing effective, it does not foreclose th e Commission from taking any action with
respect to the filing;

Tod Woolf
RXi Pharmaceuticals Corporation May 18, 2009 Page 3   ‚ 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 staff comments a nd the declaration of effectiveness 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 advi sed that the Division of En forcement has access to all
information you provide to the staff of the Di vision 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 conf irmation of the fact that t hose requesting acceleration are
aware of their respective re sponsibilities under the S ecurities Act of 1933 and the
Securities Exchange Act of 1934 as they rela te 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 acce leration of the effective date.

We direct your attention to Rules 46 0 and 461 regarding requesting acceleration
of a registration statement.  Please allow ad equate time after the filing of any amendment
for further review before submitting a request for acceleration.  Please provide this request at least two business days in a dvance of the requested effective date.
 Please contact Nandini Acharya at (202) 551-3495 or me  at (202) 551-3715 with
any questions.          S i n c e r e l y ,             J e f f r e y  P .  R i e d l e r          A s s i s t a n t  D i r e c t o r   cc: Marc A. Rubenstein, Esq.
Ropes & Gray LLP One International Place Boston, MA 02110