SecProbe.io

December 23, 2011
 Via E-mail

Louis Miceli Chief Financial Officer CommVault Systems, Inc 2 Crescent Place Oceanport, NJ 07757
Re: CommVault Systems, Inc.
  Form 10-K for Fiscal Year Ended March 31, 2011
Filed May 17, 2011 File No. 001-33026

Dear Mr. Miceli:
 We have reviewed your filing and have the following comments.  In some of our
comments, we may ask you to provide us with  information so we may better understand your
disclosure.
 Please respond to this letter within ten business days by amending your filing, by
providing the requested information, or by advi sing us when you will provide the requested
response.  If you do not believe our comments apply to your fact s and circumstances or do not
believe an amendment is appropriate, pl ease tell us why in your response.

After reviewing any amendment to your filing and the information you provide in
response to these comments, we ma y have additional comments.
            Form 10-K for Fiscal Year Ended March 31, 2011

 Management’s Discussion and Analysis of Fi nancial Condition and Results of Operations

 Liquidity and Capital Resources, page 42

1. We note that a substantial am ount of your revenue is genera ted from outside the United
States.  We also note the company has a signi ficant amount of cash and cash equivalents
as of March 31, 2011.  Tell us your considera tion to disclose the amount of cash and
investments that are currently held outside of the United States and the amounts, if any,
that are subject to restriction from and/or  additional taxes upon repatriation. We refer you
to Item 303(a)(1) of Regulation S-K a nd Section IV of SEC Release 33-8350.

 Mr. Louis Miceli CommVault Systems, Inc December 23, 2011 Page 2
 Notes to Consolidated Financial Statements

 Note 8 Stock Plans, page 62

2. We note from your disclosures on page 63 that  you will continue to use the simplified
method to estimate the expected term in  your option valuation model until you have
enough historical experience to provide a reas onable estimate of expected term.  Please
explain further why you continue to believe th at you do not have suffici ent historical data
upon which to estimate the expected term of your options.  In this regard, we note that
over 6.0 million options have been exercised dur ing the past five years since you became
a public entity.  Tell us when management e xpects that sufficient information will be
available.  We refer you to Question 6 of SAB Topic 14.D.2.

We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing include s the information the Securities Exchange Act of
1934 and all applicable Exchange Act rules requir e.  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.
 In responding to our comments, please provi de a written statement from the company
acknowledging that:

 the company is responsible for the adequacy an d accuracy of the disclo sure in the filing;

 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 comments as  a defense in any proceeding initiated by
the Commission or any person under the federa l securities laws of  the United States.

You may contact Melissa Ki ndelan, Staff Accountant at  (202) 551-3564 if you have
questions regarding comments on th e financial statements and related matters.  If you require
further assistance, do not hesitate  to contact me at (202) 551-3499.

Sincerely,
   /s/ Patrick Gilmore for
Kathleen Collins Accounting Branch Chief