Mail Stop 6010						December 19, 2006




Safi R. Bahcall, Ph.D.
President and Chief Executive Officer
Synta Pharmaceuticals Corp.
45 Hartwell Avenue
Lexington, Massachusetts 02421

	Re:	Synta Pharmaceuticals Corp.
		Registration Statement on Form S-1
		Filed November 22, 2006
		File No. 333-138894

Dear Dr. Bahcall:

	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.

FORM S-1

General

1.  Please provide us proofs of all graphic, visual, or
photographic
information you will provide in the printed prospectus prior to
its
use, for example in a preliminary prospectus.  Please note we may
have comments regarding these materials.


2.  Please note that when you file a pre-effective amendment
containing pricing-related information, we may have additional
comments.  As you are likely aware, you must file this amendment
prior to circulating the prospectus.
3.  Please note that when you file a pre-effective amendment that
includes your price range, it must be bona fide.  We interpret
this
to mean your range may not exceed $2 if you price below $20 and
10%
if you price above $20.
4.  Please note that where we provide examples to illustrate what
we
mean by our comments, they are examples and not complete lists.
If
our comments are applicable to portions of the filing that we have
not cited as examples, please make the appropriate changes in
accordance with our comments.
5.  Comments related to your request for confidential treatment
will
be provided under separate cover.  Please be advised that we will
not
be in a position to consider a request for acceleration of
effectiveness of the registration statement until we resolve all
issues concerning the confidential treatment request.

Cover page
6.  Please remove the phrase "joint book-running managers."

Prospectus Summary, page 1

7.  Please expand the discussion to briefly indicate that you
currently have no products approved for commercial sale and you
have
not generated any revenues from commercial sales.

8.  We note your discussion on page one of Fast Track designation
for
your STA-4783 product.  Please revise your discussion to explain
what
Fast Track designation signifies and to clarify that such status
does
not mean you may eliminate any phases of clinical study.  Please
also
state how Fast Track status facilitates the drug development and
regulatory review process.

Our Oncology Programs, page 1
STA-4783

9.  We note the statistical information in the last paragraph on
page
1.  Please clarify whether the potential market for STA-4783 will
include anyone suffering from metastatic melanoma or a smaller
group
of sufferers.  If you anticipate the use of STA-4783 for
metastatic
melanoma will be indicated for only some patients, you should
identify the indication and disclose the number of individuals who
would meet that indication.




10.  Please expand the discussion to indicate when you filed IND`s
for each of your drug candidates.
11.  Throughout the document, including your business section, you
reference several industry sources and various statistics and
other
figures, including statements relating to the market in which you
expect your products to compete.  Please provide us supplementally
with copies of the sources from which you obtained the statistical
and other data for the following statements.  These copies should
be
marked to indicate the information supporting your statements.

* "We believe this is the first blinded clinical trial of a drug
candidate for the treatment of metastatic melanoma in 30 years to
meet its primary endpoint with statistical significance."  Page 1.
* "Melanoma is the deadliest type of skin cancer and is the sixth
most commonly diagnosed cancer in the United States.  The National
Cancer Institute has estimated that the prevalence of melanoma in
the
United States, or the number of patients alive who have been
diagnosed with the disease, is more than 660,000.  The American
Cancer Society estimates that in 2006, the incidence, or number of
newly diagnosed cases, in the United States will be approximately
62,000, with 8,000 deaths from the disease.  According to
GLOBOCAN,
the worldwide incidence of melanoma in 2002 was 160,177, with
40,781
deaths from the disease."  Pages 1 and 61.
* "The World Health Organization estimates that more than 11
million
people are diagnosed with cancer every year worldwide, and seven
million people die from the disease annually.  The American Cancer
Society estimates that approximately 1.4 million people in the
United
States will be diagnosed with cancer in 2006, and approximately
565,000 people will die from the disease.  Chemotherapeutics are
the
second largest therapeutic class of pharmaceuticals in the world,
with global sales of $28.5 billion in 2005."  Page 61.
* "In 2001, the American Joint Committee on Cancer estimated that
approximately 15% of patients with melanoma were initially
diagnosed
with advanced-stage disease, which consists of stage III and stage
IV
melanoma.  However, recent scientific articles suggest that this
percentage may grow significantly with the increased use of
improved
diagnostic techniques.  In a study reported in the February 2003
issue of The Journal of the American College of Surgeons,
approximately 38% of 175 patients originally diagnosed with stage
I
or stage II melanoma should have been categorized with stage III
melanoma."  Page 62.
* "In metastatic melanoma, the response rate of single agent
paclitaxel has been reported as less than 20%.  A study published
in
2002 in Cancer Investigation showed that combining DTIC and
paclitaxel for the treatment of metastatic melanoma was not
superior
to using each agent alone."  Page 62.

To the extent that the statements are your beliefs or estimates,
please present the basis for your estimates and beliefs.  To the
extent that these estimates are based on information obtained from



other reports, you should provide these reports and explain how
they
were used to form your estimates.
12.  We note the reference to the trials anticipated to be
initiated
in 2007.  Where applicable throughout the prospectus, please
update
the discussion concerning the status and timing of trials and
related
events, e.g., pages 1 and 3.

Risks associated with our business", page 4

13.  Please revise the embedded list of risks to present this
information in bullet point format.

"If we fail to obtain the capital necessary to fund our
operations....", page 11

14.  It appears this risk factor describes two risks: the risk of
not
being able to raise the necessary funds and the risk of potential
negative effects to shareholders as a result of raising additional
funds.  Please discuss these distinct risks in two separate risk
factor headings and discussions.

"We deal with hazardous materials....", page 19
15.  Please quantify the extent of your insurance coverage.

"We rely on third parties to conduct our clinical trials....",
page
19

16.  Please identify the third parties you substantially rely upon
for conducting your clinical trials.  Also, to the extent you have
any agreements with such parties, please so indicate and describe
in
your business section the material terms of the agreement(s).  You
should also file the agreements as exhibits to the registration
statement.  If you have determined that you are not substantially
dependent on these parties, please provide us with an analysis
supporting this determination and disclose the number of parties
you
engage to conduct your clinical trials.

"We have no manufacturing capacity and depend on third-party
manufacturers....," page 20

"We intend to use a single manufacturer for the supply of STA-4783
.....", page 21

17.  Please identify your third-party manufacturers.  Also, to the
extent you have any agreements with such parties, please so
indicate
and describe in your business section the material terms of the
agreement(s).  You should also file the agreements as exhibits to
the
registration statement.  If you have determined that you are not
substantially dependent on these parties, please provide us with
an
analysis supporting this determination and disclose the number of
parties you may engage to manufacture your drug candidates.





"If our patent position does not adequately protect our drug
candidates....", page 22
18.  We note there may be instances where your licensors and
collaborators may be primarily or wholly responsible for the
maintenance of patents and prosecution of patent applications.  If
you do not have the obligation to take action, do you have the
right
to take necessary action if the other party does not?

"If a successful product liability claim or series of claims is
brought against us....", page 26

19.  Please expand the discussion to quantify the amount of
product
liability insurance coverage you currently maintain.

"Our future success depends on our ability to retain our chief
executive officer....", page 28

20.  Please expand the discussion to identify the other members of
your executive and scientific teams upon whom you are dependent
and
who are not specifically identified on page 92.

"Investors in this offering will pay a much higher price....",
page
32
21.  Please revise this discussion to also state that shareholders
will contribute __% of the total amount to fund the registrant but
will only own __% of the outstanding shares.

Use of proceeds, page 34

22.  Please refer to the second bullet.  Please state where you
expect to be in the clinical testing process with apilimod after
the
application of these proceeds, i.e. initiate Phase 2b trial,
complete
Phase 2b trial, complete a Phase 2b and initiate a Phase III
trial,
etc.
23.  Please describe for which "general corporate purposes" you
plan
to use the proceeds from this offering.  State an approximate
dollar
amount for each use.
24.  We note you may use a portion of the net proceeds to fund
possible acquisitions of, or invest in, technologies, products, or
companies that complement your business.  Please clarify from
which
currently specified allocation(s) you will take funds for such
possible use.










Management`s Discussion and Analysis of Financial Condition and
Results of ..., page 42

Financial Operations Overview, page 43

Research and Development, page 43

25.  Please revise your table here to attribute the IPR&D expenses
to
each acquired product for each period presented including
inception
to date. To the extent that such expenses can not be reasonably
attributed to specific products (whether currently or no longer
pursuing), please include the amount of these costs for each
period
presented, in total and by nature of the costs.

Critical Accounting Policies and Estimates, page 46

Stock-Based Compensation, page 47

26.  Please expand your current disclosure to include the
following:

a. Qualitatively and quantitatively discuss the significant
factors,
assumptions and methodologies used in the mid-December 2005
valuation
and November 2006 retrospective valuation performed, including the
actual amount of enterprise value and a discussion as to how that
amount was estimated.

b. Qualitatively and quantitatively discuss the specific factors
and
assumptions utilized in your probability-weighted, discounted cash
flow analysis.  Describe what "probability factors and discount
rate"
were considered and how you determined that they were reasonable
and
appropriate.

c. Qualitatively and quantitatively disclose how your analysis
considered the probability of selling the company, the probability
of
ultimately completing an initial public offering or not, and how
the
ultimate success of your "two most advanced drug candidates" were
weighted in your calculation.

d. Once you can reasonably estimate the IPO price, qualitatively
and
quantitatively discuss each significant factor contributing to the
difference between each valuation and the estimated IPO price.

27.  You state at the bottom of page 48 that you contemporaneously
estimate the fair value of the equity instruments issued, but you
also go on to state on page 49 that you performed a retrospective
analysis in November 2006.  If you have performed contemporaneous
valuations of your equity instruments please explain to us what
necessitated the need to perform a retrospective valuation.

28.  Please demonstrate how you determined the amount of the
incremental stock-based compensation associated with the repriced
options disclosed here in this note, including how you determined
the
aggregate amount of common stock to be purchased. We note that at
December 31, 2005, the total number of options outstanding with
exercise prices equal to or greater than $4 were approximately 4.9
million, and the remaining weighted average contractual life
ranged
between eight and ten years.

29.  Please tell us how you determined that the difference between
the value of the common stock and the Series A convertible
preferred
stock purchase price was appropriate.  In so doing, elaborate on
the
perceived value of the adjustable conversion feature of the Series
A
convertible preferred stock.

Safety profile, page 67

      30.  Please expand the discussion to define the terms
"neutropenia" and "neuropathy."

ACCOUNTING COMMENTS

December 31, 2005 Financial Statements

Consolidated Statements of Cash Flows, page F-26

31.  Please explain why you present of restricted cash within the
operating section of the statement of cash flows.  Include
references
to specific literature relied on in your determination.


*	*	*

General

	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.

	You may contact Tabatha Akins at (202) 551-3658 or Joseph
Roesler at (202) 551-3628 if you have questions regarding comments
on
the financial statements and related matters.  Please contact John
Krug at (202) 551-3862, or me at (202) 551-3715 with any other
questions.

								Sincerely,


								Jeffrey Riedler
								Assistant Director

cc:	Wendy E. Rieder, Esq.
	Jonathan L. Kravetz, Esq.
	Patrick O`Brien, Esq.
Dr. Safi R. Bahcall
Synta Pharmaceuticals Corp.
December 19, 2006
Page 8