AGREEMENT

Exhibit 10.51

AGREEMENT

This AGREEMENT (the “Agreement”), is entered into as of [                    ], by and between Deltek Systems, Inc., a Virginia corporation (the “Company”), and [                    ] (the “[Director/Executive]”).

WHEREAS, the [Director is a non-employee director of the Company/ Executive is an executive officer of the Company]; and

WHEREAS, on [                    ], the [Director/Executive] purchased [                    ] shares of common stock, par value $0.001 per share, of the Company (the “Common Stock”), for a purchase price of $7.22 per share (the “Share Purchase”); and

WHEREAS, at the time of the Share Purchase, the Company had concluded that the fair value of a share of Common Stock was $7.22; and

WHEREAS, the Company subsequently obtained a third party valuation of the Common Stock which concluded that the fair value of a share of Common Stock at the time of the Share Purchase was $9.00 per share, rather than $7.22 per share; and

WHEREAS, by reason of this valuation difference, the [Director/Executive] acquired [                    ] shares of Common Stock in excess of the shares she would have acquired in connection with the Share Purchase had a price of $9.00 per share been used (such [                    ] shares, the “Excess Shares”);

NOW, THEREFORE, in consideration of the premises and the mutual covenants set forth in this Agreement, and for good and valuable consideration, receipt of which is acknowledged, the Company and [Director/Executive], intending to be legally bound, agree as follows:

1. Return of the Excess Shares to the Company. The [Director/Executive] hereby delivers to the Company, and the Company hereby accepts from the [Director/Executive], [                    ] shares of Common Stock, which number of shares constitutes the Excess Shares.

2. Issuance of a New Stock Certificate. The [Director/Executive] authorizes and directs the Company, on her behalf and in her stead, to effect such delivery by cancelling stock certificate number [                    ] and issuing a stock certificate (the “Replacement Certificate”) to the [Director/Executive] representing [                    ] shares. The Replacement Certificate shall bear the legend set forth in Section 7 of the Stock Purchase Agreement, dated as of [                    ], to which the Company and the [Director/Executive] are parties (the “Stock Purchase Agreement”) and shall continue to be subject to the terms and conditions of the Stock Purchase Agreement and the Shareholder’s Agreement, dated as of [                    ], to which the Company and the [Director/Executive] are parties (the “Shareholder’s Agreement”).

3. Amendment of the Stock Purchase Agreement. This Agreement modifies the Stock Purchase Agreement by deleting the number [                    ] in Section 1(a) of the Stock Purchase Agreement and inserting the number [                    ] in its place.

4. No Effect on Other Agreements. No provision of this Agreement shall be deemed to alter or impair the rights or obligations of the Company or the [Director/Executive] under the Shareholder’s Agreement or, except as set forth in Section 3 of this Agreement, under the Stock Purchase Agreement.

IN WITNESS WHEREOF, each party hereto has caused this Agreement to be duly executed as of the date first written above.

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