SCHEDULE 14A
                                 (RULE 14a-101)

                    INFORMATION REQUIRED IN PROXY STATEMENT
                            SCHEDULE 14A INFORMATION

          PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES
                              EXCHANGE ACT OF 1934

Filed by the Registrant [X]

Filed by a Party other than the Registrant [ ]

Check the appropriate box:

<Table>
                                            
[ ]  Preliminary Proxy Statement
[ ]  Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))
[ ]  Definitive Proxy Statement
[X]  Definitive Additional Materials
[ ]  Soliciting Material Pursuant to Section 240.14a-11c or Section 240.14a-12
</Table>

                              DELTEK SYSTEMS, INC.
- --------------------------------------------------------------------------------
                (Name of Registrant as Specified In Its Charter)

- --------------------------------------------------------------------------------
                   (Name of Person(s) Filing Proxy Statement)

Payment of Filing Fee (Check the appropriate box):

[X]  No fee required.

[ ]  Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

     (1)  Title of each class of securities to which transaction applies:

          ----------------------------------------------------------------------

     (2)  Aggregate number of securities to which transaction applies:

          ----------------------------------------------------------------------

     (3)  Per unit price or other underlying value of transaction computed
          pursuant to Exchange Act Rule 0-11 (set forth the amount on which the
          filing fee is calculated and state how it was determined):

          ----------------------------------------------------------------------

     (4)  Proposed maximum aggregate value of transaction:

          ----------------------------------------------------------------------

     (5)  Total fee paid:

          ----------------------------------------------------------------------

[ ]  Fee paid previously with preliminary materials.

[ ]  Check box if any part of the fee is offset as provided by Exchange Act Rule
     0-11(a)(2) and identify the filing for which the offsetting fee was paid
     previously. Identify the previous filing by registration statement number,
     or the Form or Schedule and the date of its filing.

     (1)  Amount Previously Paid:

          ----------------------------------------------------------------------

     (2)  Form, Schedule or Registration Statement No.:

          ----------------------------------------------------------------------

     (3)  Filing Party:

          ----------------------------------------------------------------------

     (4)  Date Filed:

          ----------------------------------------------------------------------


                                                   Filed by Deltek Systems, Inc.
                                                       Pursuant to Rule 14a-6(b)
                                          of the Securities Exchange Act of 1934
                                           Subject Company: Deltek Systems, Inc.
                                                  Commission File No.: 000-22001

On May 14, 2002, Deltek Systems, Inc. issued the following press release:

                                 [DELTEK LOGO]

                    DELTEK ANNOUNCES INFORMATION CONCERNING
                SHAREHOLDER LAWSUIT AND PROXY VOTING PROCEDURES

HERNDON, VA -- MAY 14, 2002 -- DELTEK SYSTEMS, INC. (NASDAQ:DLTK),

     On or about May 6, 2002, a pleading identified as a "class action,
complaint" was filed by Carl Brown against Deltek Systems, Inc. and the six
members of its board of directors in the District Court for the Second Judicial
District in Ramsey County, Minnesota. The two counts of the complaint assert
that, in connection with the proposed going private transaction that will be
voted on at a May 31, 2002 special meeting of Deltek's shareholders, the
directors breached their fiduciary duty and duty of disclosure to Deltek's
shareholders.

     The complaint seeks (1) a declaration that the action is properly
maintainable as a class action, (2) injunctions against the consummation of the
May 31, 2002 special meeting of Deltek shareholders and completion of the merger
through which the going private transaction will be effected and (3) damages and
costs. The complaint is being filed with the SEC as an exhibit to an amendment
to Deltek's Rule 13e-3 Transaction Statement on Schedule 13E-3, which may be
viewed at www.sec.gov/edgar/searchedgar/ formpick.htm, and the description
herein of the complaint is qualified in its entirety by reference to the
complaint itself. It is possible that the plaintiff will seek to amend his
complaint in the future. If so, any such amended complaint will be filed
promptly as a further amendment to Deltek's Rule 13e-3 Transaction Statement on
Schedule 13E-3.

     Deltek and the individual defendants believe the allegations set forth in
the complaint are without merit and intend to vigorously defend the litigation.

     If the relief requested in the complaint were granted, or the pendency of
the litigation delays consummation of the transaction, such circumstances could
give DF Merger Co., Inc. (the entity formed by the deLaskis to effect the going
private transaction) the right to terminate the merger agreement. The pendency
of the litigation may make more difficult or impossible the completion of the
financing for the transaction.

     With respect to the breach of fiduciary duty claim, the complaint alleges
that none of the directors is disinterested and independent and that all of them
have breached their fiduciary duty by (1) seeking to squeeze out the company's
public shareholders for an unfair and inadequate price and (2) failing to
provide meaningful procedural protections for the minority shareholders who may
be cashed out. The plaintiff also claims that the merger agreement establishes
defensive provisions designed to protect the going private transaction from
competing third-party bids.

     The disclosure claim asserts that the defendants violated their duty of
disclosure to Deltek's shareholders by failing to disclose in the proxy
statement for the special meeting information concerning (1) the financial
interests of the special committee members in the value of the new private
entity going forward, (2) the details of a potential competing offer received by
the company, and (3) the company's


recent financial performance. Additional information concerning this claim is
set forth in Item 15 of Amendment No. 3 to Deltek's Rule 13e-3 Transaction
Statement on Schedule 13E-3 to be filed with the SEC.

     If the allegations set forth in the plaintiff's complaint or any amendment
of the complaint, or the matters summarized above, cause a Deltek shareholder to
want to change his or her vote on the approval of the Agreement and Plan of
Merger and related plan of merger dated as of February 13, 2002, the shareholder
may revoke his or her proxy. This may be done in any of the following ways:

          1. Calling a special toll free number, 1-866-283-1868, established by
     Deltek at Georgeson Shareholder Communications, Inc., 17 State Street, New
     York, New York 10004 ("Georgeson"), and speaking to a representative of
     Georgeson who will assist you in revoking your proxy and changing your
     vote.

          2. Sending a written notice stating that you would like to revoke your
     proxy, or by completing and submitting prior to the special meeting a new,
     later-dated proxy card, in each case to the following address:

                                Deltek Systems, Inc.
                                13880 Dulles Corner Lane
                                Herndon, VA 20171
                                Attention: Corporate Secretary

          3. Attending the special meeting of shareholders and voting in person.

          4. After receipt of an additional proxy card that will be mailed to
     all shareholders, voting your shares again in accordance with the
     instructions that will be included with the mailing.

     If your shares are held in "street name," you must follow directions
provided by your broker to change your vote. You should call your broker or the
toll free number, 1-866-283-1868, for assistance in this regard.

DELTEK INVESTOR RELATIONS: Babette J. Aller, Investor Relations Manager,
800-456-2009, ext. 4444; baller@deltek.com.

PUBLIC RELATIONS: K. Allen Farber, Press Officer, 800-456-2009, ext. 4544;
cell: 703-598-3585; afarber@deltek.com.