WASHINGTON, D.C. 20549


                                    FORM 8-K

                                 CURRENT REPORT

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

                                January 15, 2004
                Date of report (Date of earliest event reported)

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

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

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

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

                                 Not Applicable
          (Former Name or Former Address, if Changed Since Last Report)

Item 12. Results of Operations and Financial Condition.

      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, as amended (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, as amended, or the Exchange Act, except as
expressly set forth by specific reference in such filing.

      On January 15, 2004, NetScout issued a press release regarding its
financial results for the quarter ended December 31, 2003, its expectations of
future performance and its intention to hold a conference call regarding these
topics. NetScout's press release is furnished as Exhibit 99.1 to this report and
is incorporated herein by reference.


      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: January 15, 2004               By: /s/ David P. Sommers
                                         David P. Sommers
                                         Chief Financial Officer and Senior Vice
                                         President, General Operations

                                  EXHIBIT INDEX

Exhibit No.   Description
-----------   -----------

  99.1        Press release dated January 15, 2004.