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Via Facsimile and U.S. Mail Mail Stop 4720                                                                                                   August 10, 2009  Leonard S. Schleifer, M.D., Ph.D.    Chief Executive Officer    Regeneron Pharmaceuticals, Inc. 777 Old Saw Mill River Road Tarrytown, New York 10591-6707
Re: Regeneron Pharmaceuticals, Inc.
Form 10-K for the Fiscal Year Ended December 31, 2008 Filed February 26, 2009 File Number 000-19034

Dear Dr. Schleifer:
  We have reviewed your response to our comments and have the following additional comments.   In our comments, we ask you to provide us with information to
better understand your disclosure. Where it requests you to revise disclosure, the
information you provide should show us what the revised disclosure will look like and
identify the annual or quarterly filing, as a pplicable, in which you in tend to first include
it. If you do not believe that revised disclosu re is necessary, expl ain the reason in your
response.  After reviewing the informati on provided, we may raise additional comments
and/or request that you amend your filing.   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 on any other aspect of our
review.  Feel free to call us at the telephone numbers listed at the end of this letter.

Definitive Proxy Statement

 Performance Based Vesti ng Stock Options, page 25

1. We note your response to comment 5.  Pl ease provide proposed disclosure that
you intend to provide in your  proxy statement for the year 2009 which expands
upon your description of the “point scale system” for the vesting of your performance based vesting stock options .  Please include the following in your
proposed disclosure:

Leonard S. Schleifer, M.D., Ph.D.
Regeneron Pharmaceuticals, Inc. August 10, 2009 Page 2

• Discussion of the specific number of poi nts or range of points awarded based
on achievement of each of the development milestones you identify;
• Discussion of how the number of points  earned corresponds to the amount of
stock options that vest;
• Discussion of the minimum number of poi nts that must be earned during the
Performance Period for any of the perfo rmance based vesting options to vest;
and,
• To the extent applicable, discussion of whether the Compensation Committee
can exercise its discretion w ith regard to any of the bullets identified above.

*    *    *    *
 Please respond to these comments within  10 business days or tell us when you
will provide us with a response.  Please furnish a cover letter that keys your responses to
our comments and provide any requested inform ation.  Detailed letter s greatly facilitate
our review.  Please file y our letter on EDGAR under the form type label CORRESP.
  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 Exchange Act of 1934 and th at they have provided all information
investors require for an informed invest ment decision.  Since the company and its
management are in possession of all facts re lating to a company’s disclosure, they are
responsible for the accuracy and adequacy of the disclosures they have made.
  In connection with responding to our co mments, please provide, in your letter, a
statement from the company acknowledging that:
• the company is responsible for the adequacy  and accuracy of the disclosure in the
filing;
• staff comments or changes to disclosure  in response to staff comments do not
foreclose the Commission from taking any action with respect to the filing; and
• the company may not assert staff comme nts as a defense in any proceeding
initiated by the Commission or any person under the federal secu rities laws of the
United States.

Leonard S. Schleifer, M.D., Ph.D.
Regeneron Pharmaceuticals, Inc. August 10, 2009 Page 3
 In addition, please be advise d that the Division of Enfo rcement has access to all
information you provide to the staff of the Divi sion of Corporation Fi nance in our review
of your filing or in response to our comment on your filing.
Please contact Bryan Pitko at  (202) 551-3203 with any quest ions.  In this regard,
please feel free to cont act me at (202) 551-3715.

Sincerely,

  Jeffrey Riedler,  Assistant Director