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                                                                                                April 14, 2006

Joshua S. Boger
Chief Executive Officer
Vertex Pharmaceuticals Incorporated
130 Waverly Street
Cambridge, Massachusetts 02139-4242

Re: Vertex Pharmaceuticals Incorporated
 Form 10-K for Fiscal Year Ended December 31, 2005
 Filed March 16, 2006
 File No. 000-19319

Dear Mr. Boger:

We have limited our review of your filing to  the issues we have addressed in our
comments.  In our comments, we ask you to provide us with information so we may
better understand your disclosure.  Please be as de tailed as necessary in  your explanation.
After reviewing this information, we may raise additional comments.

 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 filings.  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.

Notes To Consolidated Financial Statements, page F-7

B.  Accounting Policies, page F-7

Revenue Recognition, page F-11
1. We have the following comments rega rding your revenue recognition policy
related to substantive milestone paym ents that are reasonably assured:

a. When you have evidence of fair value for your remaining obligations, please clarify for us why it is approp riate to then recognize that payment
as earned.  In this regard, it is uncl ear whether you consider the milestone

Joshua S. Boger
Vertex Pharmaceuticals Incorporated
April 13, 2006  Page 2
payment and the remaining obligations to be separate units of accounting.  If so, it is unclear whet her the portion of the payment attributable to the
remaining obligations should instead be deferred and recognized upon the
satisfaction of the obligations.
b. When you do not have fair value for your remaining obligations, please clarify for us why it is appropriate  to recognize the payments over the
period of performance.  In this regard, it is unclear whether you consider the substantive milestone payments and the remaining obligations as a single unit of accounting.  If so, it is unclear whether all the obligations are
satisfied over a period of time or if the payment should instead be deferred until the satisfaction of all obligations.
c. To the extent that your policy is not appropriate, pl ease provide us
proposed revisions to the policy and te ll us whether those revisions would
have had a material impact on previ ously reported financial condition or
results of operations.

K. Convertible Subordinated Notes, page F-24
2. When you issued shares to holders of your  notes in exchange for those notes,
please tell us why it was a ppropriate to calculate the loss on extinguishment based
on the incremental shares issued over the number that would have previously been
issued upon conversion of the notes under the original terms.  In so doing, please
refer to paragraphs 3(c), 20 and 21 of APB 26 and explain why you did not calculate the loss based on the excess of th e fair value of the shares issued over
the carrying amounts of the notes.
*    *    *    *

Please respond to these comments within  10 business days or tell us when you
will provide us with a response.  Please furnish a letter that keys your responses to our comments and provide the requested information.  Detailed letters gr eatly facilitate our
review.  Please file your letter on E DGAR 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 include 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:

Joshua S. Boger
Vertex Pharmaceuticals Incorporated
April 13, 2006  Page 3

• the company is responsible for the adequacy  and accuracy of the disclosure in the
filings;
• 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.

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 comments on your filing.

You may contact James Pe klenk, Staff Accountant, at (202) 551-3661, or Oscar
Young, Senior Accountant, at (202) 551-3622 if you have questions regarding the
comment.  In this regard, do not hesi tate to contact me, at (202) 551-3679.

Sincerely,

Jim B. Rosenberg
Senior Assistant Chief Accountant