UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION

                              WASHINGTON, DC 20549

                                   FORM 8-K/A

                               AMENDMENT NO. 1 TO

                                 CURRENT REPORT

     Pursuant to Section 13 or 15 (d) of the Securities Exchange Act of 1934

                        Date of Report: September 3, 2004

                (Date of earliest Event Reported: June 25, 2004)

                                ESSEX CORPORATION
             (Exact name of Registrant as specified in its charter)

Commission File No.  0-10772

         Virginia                                                   54-0846569
(State or other jurisdiction of                          (IRS Employer ID No.)
incorporation or organization)

         9150 Guilford Road
         Columbia, Maryland                                         21046-2306
(Address of principal executive office)                             (Zip Code)

Registrant's telephone number, including area code:             (301) 939-7000

Check  the  appropriate  box  below if the  Form  8-K  filing  is  intended  to
simultaneously  satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

[  ]   Written communications pursuant to Rule 425 under the Securities Act
       (17 CFR 230.425)

[  ]   Soliciting material pursuant to Rule 14a-12 under the Exchange Act
       (17 CFR 240.14a-12)

[  ]   Pre-commencement communications pursuant to Rule 14d-2(b) under the
       Exchange Act (17 CFR 240.14d-2(b))

[  ]   Pre-commencement communications pursuant to Rule 13e-4(c) under the
       Exchange Act (17 CFR 240.13e-4(c))





                                ESSEX CORPORATION


                  AMENDMENT NO. 1 TO CURRENT REPORT ON FORM 8-K

           We hereby amend our Current Report on Form 8-K filed on July 6, 2004,
which  announced  the  completion  on  June  25,  2004  of  our  acquisition  of
substantially  all the assets of Performance  Group,  Inc. (PGI). The purpose of
this amendment is to file Performance  Group,  Inc.  Financial  Statements as of
December 26, 2003 and December 27, 2002,  together with Auditors' Report and the
Pro Forma Financial Information (unaudited)

Item 2.01  Completion of Acquisition or Disposition of Assets

           Pursuant to an Asset Purchase Agreement dated as of June 3, 2004 (the
           "Agreement") by and among the Registrant,  Performance  Group, Inc. a
           Virginia  corporation  ("PGI"),  and Ronald Horn, Sole Shareholder of
           PGI. The Merger  became  effective as of June 25, 2004.  The terms of
           the Merger are contained in the Agreement, which was previously filed
           as an  Exhibit  to  Registrant's  report on Form 8-K  filed  with the
           Commission on July 6, 2004.

Item 9.01  Financial Statements and Exhibits

           (a)  Financial Statements of Business Acquired

                (1)  Performance Group, Inc.  Financial  Statements  for  the 52
                     week periods ended December 26, 2003 and December 27, 2002,
                     together  with  Auditors'  Report  are  attached  hereto as
                     Exhibit 99.2 and are incorporated herein by reference.

           (b)  Pro  Forma  Financial  Information  (unaudited)  presenting  the
                effect of the Merger as if it had been completed on December 29,
                2002 for the pro forma consolidated statements of operations are
                attached hereto as Exhibit 99.3 and are  incorporated  herein by
                reference.  A pro forma balance sheet is not presented since the
                transaction is reflected in the Company's  interim balance sheet
                filed as part of its Form 10-Q for the  quarter  ended  June 27,
                2004.

           (c)  Exhibits
                2.1   Asset  Purchase  Agreement  dated as of June 3,  2004 (the
                      "Agreement")  by and  among  the  Registrant,  Performance
                      Group,  Inc. a Virginia  corporation  ("PGI"),  and Ronald
                      Horn,  Sole  Shareholder  of PGI,  effective June 25, 2004
                      (excluding   Exhibits  and  Schedules)   (incorporated  by
                      reference  from  Exhibit 2.1 to the  Registrant's  Current
                      Report on Form 8-K filed July 6, 2004)

                99.1  Press  release  dated  June  28,  2004   (incorporated  by
                      reference  from Exhibit 99.1 to the  Registrant's  Current
                      Report on Form 8-K filed July 6, 2004)

                99.2  Performance  Group,  Inc.  Financial  Statements for the
                      52 week  periods  ended  December 26,  2003 and December
                      29, 2002, together with Auditors' Report

                99.3  Pro Forma Financial Information (unaudited)

                      o Consolidated Statement of Operations for the fiscal year
                        ended December 28, 2003

                      o Consolidated Statement of  Operations for  the six month
                        period ended June 27, 2004

                                       2



                               ESSEX CORPORATION


                                   SIGNATURES

           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.

                                      ESSEX CORPORATION
                                      (Registrant)



                                      /S/ LISA G. JACOBSON
                                      -----------------------------------
DATE:  September 3, 2004              Lisa G. Jacobson
                                      Executive Vice President & Chief Financial
                                      Officer


                                       3



                                ESSEX CORPORATION


                                  EXHIBIT INDEX

                    (Pursuant to Item 601 of Regulation S-X)

Exhibit
NUMBER          DESCRIPTION AND METHOD OF FILING

2.1             Asset  Purchase  Agreement  dated  as of  June  3,  2004  (the
                "Agreement") by and among the Registrant,  Performance  Group,
                Inc. a Virginia  corporation  ("PGI"),  and Ronald Horn,  Sole
                Shareholder  of  PGI,  effective   June 25, 2004,   previously
                filed.

99.1            Press release dated June 28, 2004, previously filed.

99.2            Performance Group, Inc.  Financial  Statements for the 52 week
                periods  ended   December 26, 2003   and  December  27,  2002,
                together with Auditors' Report filed herewith.

99.3            Pro Forma Financial Information (unaudited) filed herewith.