EXHIBIT 99.2

                CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,

                             AS ADOPTED PURSUANT TO

                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the ManTech International Corporation (the "Company") Annual
Report on Form 10-K for the period ending December 31, 2003 as filed with the
Securities and Exchange Commission on the date hereof (the "Report), I, John A.
Moore, Jr., Chief Financial Officer of the Company, certify pursuant to 18
U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley
Act of 2002, to the best of my knowledge, that:

(1) The Report fully complies with the requirements of Section 13 (a) or 15(d)
of the Securities Exchange Act of 1934, as amended; and

(2) The information contained in the Report fairly presents, in all material
respects, the financial condition and results of operations of the Company.

This certificate is being made for the exclusive purpose of compliance by the
Chief Financial Officer of the Company with the requirements of Section 906 of
the Sarbanes-Oxley Act of 2002, and may not be disclosed, distributed or used by
any person or for any reason other than as specifically required by law.

Date:  March 31, 2003

By:    /s/ John A. Moore, Jr.
       -------------------------------------
Name:  John A. Moore, Jr.
Title: Executive Vice President, Chief
       Financial Officer, Treasurer and Director