Mail Stop 6010


	November 29, 2006


Valentin P. Gapontsev, Ph.D.
Chief Executive Officer and Chairman of the Board
IPG Photonics Corporation
50 Old Webster Road
Oxford, Massachusetts  01540

      Re:	IPG Photonics Corporation
      Amendment No. 4 to Registration Statement on Form S-1
      Filed on November 24, 2006
		File No. 333-136521

Dear Dr. Gapontsev:

      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.

General

1. We understand from your counsel that your Regulation D filing
on
October 2, 2006 relates to option grants made to your officers and
directors during 2006.  Please tell us where you have disclosed
such
option grants in your prospectus.

We are subject to various environmental laws, page 17

2. We note your response to prior comment 1.  We also note,
however,
that your disclosure that you could "incur other significant
expenses
in order to remain in compliance with such laws and regulations"
continues to imply that you may incur significant expenses as a
result of your compliance with current laws.  If still true,
please
revise your disclosure so that it is consistent with your prior
response to comment 1 that you do not believe the costs to
maintain
compliance with current environmental laws to be material.  If you
do
believe that you will incur significant costs in order to remain
in
compliance with current laws, please disclose why and what costs
you
will incur.

Stock Option Grants, page 75

3. We note your disclosure indicates that the options granted had
an
exercise price equal to the "fair market value" of your common
stock
on the date of the grant.  We, note however, that there was no
trading market for your common stock during the period in which
the
options were granted.  As such, please revise your disclosure to
be
consistent with paragraph J.17 of the Division of Corporation
Finance`s Manual of Publicly Available Telephone Interpretations
(July 1997).

4. We also note the disclosure you have added prior to the table
that
the options were granted at an exercise price equal to the fair
market value on the date of the grant "unless our board of
directors
or compensation committee determines otherwise on the date of
grant."
Given the quoted disclosure that you have added, it is unclear
whether your option grants were indeed granted at an exercise
price
equal to the fair market value on the date of the grant.  Please
revise so that your disclosure in this regard is clear.

Principal and Selling Stockholders, page 81

5. From footnotes 16 and 22, it is unclear whether the selling
shareholders currently hold the offered shares.  The first
sentence
of the footnotes states when the offered shares were acquired.
Later
the footnotes say that the offered shares underlie preferred stock
that is not yet converted.  Please clarify.

Certain Relationships and Related Party Transactions

Transactions with Dr. Valentin P. Gapontsev, page 86

6. We note your revised disclosure in response to prior comment 7.
Please tell us how your disclosure in your "Certain Relationships
and
Related Party Transactions" section is reconcilable to the amount
set
forth opposite your line item entitled "Employee and shareholder
loans repaid" in your Consolidated Statements of Cash Flows for
the
nine months ended September 30, 2006 on page F-6.

*  *  *  *  *

      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 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.

	You may contact Eric Atallah at (202) 551-3663 or Jay Webb at
(202) 551-3603 if you have questions regarding comments on the
financial statements and related matters.  Please contact Tim
Buchmiller at (202) 551-3635 or me at (202) 551-3617 with any
other
questions.

      					Sincerely,



      					Russell Mancuso
      					Branch Chief

cc (via fax): 	Robert W. Ericson, Esq.
		David A. Sakowitz, Esq.
Valentin P. Gapontsev, Ph.D.
IPG Photonics Corporation
November 29, 2006
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