WASHINGTON, D.C. 20549


                                    FORM 8-K

                                 CURRENT REPORT

                     PURSUANT TO SECTION 13 OR 15(D) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                                 April 30, 2003
                Date of report (Date of earliest event reported)

                             NetScout Systems, Inc.
             (Exact name of Registrant as specified in its charter)

             Delaware                    0000-26251              04-2837575
------------------------------- ----------------------------- ------------------
(State or Other Jurisdiction of   (Commission File Number)    (I.R.S. Employer
Incorporation or Organization)                               Identification No.)

                               310 Littleton Road
                          Westford, Massachusetts 01886
                    (Address of Principal Executive Offices)

                                 (978) 614-4000
               Registrant's telephone number, including area code

                         Exhibit Index Located on Page 4

                                     - 2 -

Item 7. Financial Statements, Pro Forma Financial Information and Exhibits.

      (a) Financial statements of businesses acquired. Not applicable.

      (b) Pro forma financial information. Not applicable.

      (c) Exhibits.

Exhibit No.    Description

99.1           Press release dated April 30, 2003.

Item 9. Regulation FD Disclosure. (The information below is being furnished
under Item 12. Results of Operations and Financial Condition.)

      This Current Report on Form 8-K of NetScout Systems, Inc. (the "Company")
is intended to be furnished under "Item 12. Results of Operations and Financial
Condition" but is instead furnished under "Item 9. Regulation FD Disclosure" in
accordance with Securities and Exchange Commission Release No. 33-8216. The
following information and the Exhibit attached hereto shall not be deemed
"filed" for purposes of Section 18 of the Securities Exchange Act of 1934 (the
"Exchange Act") or otherwise subject to the liabilities of that section, nor
shall it be deemed incorporated by reference in any filing under the Securities
Act of 1933 or the Exchange Act, except as expressly set forth by specific
reference in such filing.

      On April 30, 2003, the Company issued a press release and plans to hold a
conference call regarding its financial results for the quarter and year ended
March 31, 2003. The Company's press release is furnished as Exhibit 99.1 to this
report and is incorporated herein by reference.

Use of Non-GAAP Financial Information

      To supplement our condensed consolidated financial statements presented in
the press release in accordance with accounting principles generally accepted in
the United States ("GAAP"), the Company uses non-GAAP measures of operating
results, net loss, net income, net loss per share and net income per share,
which are adjusted from results based on GAAP to exclude non-cash acquisition
and equity based charges, namely costs associated with the Company's acquisition
of NextPoint Networks, Inc. in July 2000 and costs associated with stock based
compensation. Management believes these non-GAAP financial measures enhance the
user's overall understanding of our current financial performance and our
prospects for the future and, additionally, uses these non-GAAP financial
measures for the general purpose of analyzing and managing the Company's
business. Specifically, we believe the non-GAAP financial measures provide
useful information to both management and investors by excluding certain charges
that we believe are not indicative of our core operating results. In addition,
we believe that the investment community has historically used our non-GAAP
financial results to evaluate our financial performance, and we have
historically reported both GAAP and non-GAAP results to the investment
community. The presentation of this additional information is not meant to be
considered superior to, in isolation from or as a substitute for results
prepared in accordance with GAAP.

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      Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                               NETSCOUT SYSTEMS, INC.

Date: April 30, 2003                      By:
                                              David P. Sommers
                                              Chief Financial Officer and Senior
                                              Vice President, General Operations

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                                  EXHIBIT INDEX

Exhibit No.    Description

99.1           Press release dated April 30, 2003.