Via Facsimile
      June 27, 2005
John D. Villas
Chief Financial Officer
Entegris, Inc.
3500 Lyman Boulevard
Chaska, Minnesota 55318

Re:	Entegris, Inc.
	Registration Statement on Form S-4
	File No. 333-124719
	Amended June 13, 2005

Dear Mr. Villas:

      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.
In some of our comments, we may ask you to provide us with
information so we may better understand your disclosure.  After
reviewing this information, we may raise additional comments.

      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 any other aspect
of
our review.  Feel free to call us at the telephone numbers listed
at
the end of this letter.

Summary, page 9
The Merger, page 10

1. Please elaborate on the types of products, markets, and
operations
the combined company will have.  Describe the complementary
aspects
of each company`s operations and products in greater detail.

2. Please disclose the number of outstanding Mykrolis stock
options
and restricted stock units that you will convert in the merger.




Opinion of Mykrolis` Financial Advisor, page 56

3. We reissue comment 37 of our June 3, 2005 letter.  Please
either
describe the other information considered by Citigroup in arriving
at
its opinion or delete the reference.

Exhibit 5-Legal Opinion

4. Please disclose the state law upon which this opinion is based.

Exhibit 8.1-Tax Opinion

5. It is not clear which statements in the proxy
statement/prospectus
constitute "statements of law or legal conclusions."  Please
clarify
here and in Exhibit 8.2.

6. We note the paragraph beginning "this opinion is expressed as
of
the date hereof...." here and in Exhibit 8.2.  If you retain this
paragraph, the opinion must be dated as of the date of
effectiveness.
Otherwise, please delete the paragraph.

Closing Comments

      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
comments and provides any requested 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 filing to be certain that the
filing includes all information 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 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 staff comments and 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 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 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.

      We direct your attention to Rules 460 and 461 regarding
requesting acceleration of a registration statement.  Please allow
adequate 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 advance of the requested
effective date.

      Please contact Craig Slivka at (202) 555-3729 or the
undersigned Branch Chief who supervised review of your filings at
(202) 551-3767, with any questions.

Sincerely,


      Jennifer Hardy
      Branch Chief


cc:	Douglas P. Long, Esq.
	Fax: (612) 766-1600
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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549-0404

         DIVISION OF
CORPORATION FINANCE