SecProbe.io

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Mail Stop 4-6

April 27, 2005

Mr. Yuchun Lee
Chief Executive Officer
Unica Corporation
Reservoir Place North
170 Tracer Lane
Waltham, Massachusetts 02451-1379

Re:	Unica Corporation
	Amendment No. 4 to Registration Statement on Form S-1
	File No. 333-120615

Dear Mr. Lee:

      We have reviewed your amended filing and have the following
comments.

Management`s Discussion and Analysis of Financial Condition and
Results of Operations

Stocked-Based Compensation, pp. 32-39

1. Tell us if you used a third party to review your assessments
and,
if so, provide detail of any revisions or corrections they made.

2. Verify to us that your discounted cash flow assumptions are
consistent with internal projections used by management, presented
to
the board of directors and provided to bankers, underwriters or
other
parties.

3. We note your use of an unrelated valuation specialist to
determine
the fair value of your common stock as of December 31, 2004.  When
referencing an independent valuation consultant as an expert, you
need to disclose the name of expert and include the expert`s
consent
with the filing.  If not, the reference can be removed.  Refer to
Section 436(b) of Regulation C and footnote 60 to paragraph 179 of
the AICPA Practice Aid "Valuation of Privately-Held-Company Equity
Securities Issued as Compensation."

4. Please consider removing the notion of reassessment or clearly
explain why and when the reassessment was performed for the grants
issued on April, July and October 2004.  Also, disclose why the
reassessment was acceptable.  The current disclosure can be
confusing
to investors when you reference different fair values such as the
board-approved estimates or internally developed value versus
reassessed fair value.  As appropriate for any revision, disclose
whether the valuations were retrospective or contemporaneous.

5. The April 2004 reassessment on page 35 notes that the board of
directors approved management`s financial projections and
determined
that the discount rate used by Huron was appropriate.  Revise to
disclose the discount rate used as a significant assumption and
tell
us the assumed growth rate and liquidity rate.

6. On page 35, 36 and 37 you refer to $6.75, $9.00 and $10.50 as
the
internally developed valuations in April, July and October 2004.
It
is unclear if these values are referring to the reassessment or
the
preliminary valuation.  Revise to clarify these values as the
preliminary valuations made by you at the date of grant.

7. Confirm to us that comparable companies were used for the
market
approach at each valuation date and tell us how management
determined
that those companies were in fact comparable.

8. On page 37, you note that the discount rate is decreased for
the
October 2004 valuation.  Revise to disclose the decreased discount
rate.

9. On page 38, we note the preliminary valuation of your common
stock
in January 2005 is $9.00 and the mid-point of your offering price
in
March 2005 is $10.50 which reflects a 16% increase.  Please
address
following:

* We note the underwriters used a market multiple approach in
determining your offering price.  In view of the underwriters
approach, tell us why your use of market multiple approach and
discounted cash flows is reasonable for the January 2005
valuation.

* Tell us if comparable software company stocks increased in a
similar fashion during the period of January to March 2005.

10. In paragraph six of page 38, please revise the last sentence
to
indicate that the definition of intrinsic value applies not to "an
option" but to "these" options, those comprising the March 31,
2005
intrinsic value of outstanding vested and unvested options of
$16.4
million.

Supplemental Information Binder, Tab 2 - April 26, 2004
Reassessment

11. Where you use two or three approaches: market multiple,
discounted cash flow and comparable companies when you
"reassessed"
the fair value of common stock, explain to us the reason for the
disparity in the respective valuation amounts.

12. On page 3 of the April 26, 2004 reassessment, we note the
footnote "IPO composite weighted at 17% on a median basis."  Tell
us
what this means and how it was derived.  Please also explain how
you
determined the "Baseline Comparables" of 2.8, "IPO Comparables" of
4.53 and "All Comparables" of 3.26.

*              *              *              *

      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 supplemental 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.

      You may contact Kari Jin at (202) 842-5552, or me at (202)
942-
2949, if you have questions or comments on the financial
statements
and related matters.  Please contact Daniel Lee at (202) 942-1871
with any other questions.  If you need further assistance, you may
contact Barbara C. Jacobs, Assistant Director, at (202) 942-1800.

	Sincerely,

	Craig Wilson
	Senior Assistant Chief Accountant

cc:	Via Facsimile
	Peter B. Tarr, Esq.
	Mark L. Johnson, Esq.
	Wilmer Cutler Pickering Hale and Dorr LLP
	60 State Street
	Boston, Massachusetts 02109
	Telephone: (617) 526-6000
	Facsimile:  (617) 526-5000

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