UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 10)*

DELTEK, INC.

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

24784L105

(CUSIP Number)

Steven B. Klinsky

New Mountain Investments II, L.L.C.

787 Seventh Avenue, 49th Floor

New York, NY 10019

(212) 720-0300

Copies to:

Paul Reinstein

Fried, Frank, Harris, Shriver & Jacobson LLP

One New York Plaza

New York, NY 10004-1980

(212) 859-8000

(Name, Address and Telephone Number of Person Authorized

to Receive Notices and Communications)

October 10, 2012

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box: o

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON New Mountain Investments II, L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON OO


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON New Mountain Partners II, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON PN


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON New Mountain Affiliated Investors II, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON PN


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Allegheny New Mountain Partners, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON PN


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON New Mountain Capital, L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON OO


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Steven B. Klinsky
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States of America
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON IN


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Kathleen deLaski
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS OO*
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States of America
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON IN

*See Item 3.


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Edward Grubb
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS OO*
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States of America
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON IN

*See Item 3.


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Onae Trust
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS OO*
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION New York
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON OO

*See Item 3.


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Alvaro Pascotto
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS OO*
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION New York
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON IN

*See Item 3.


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Daphne Jean deLaski Irrevocable Trust
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS OO*
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Virginia
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON OO

*See Item 3.


CUSIP No. 24784L105	SCHEDULE 13D

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Dana Nancy deLaski Irrevocable Trust
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [x]
3	SEC USE ONLY
4	SOURCE OF FUNDS OO*
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Virginia
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 0
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0%
14	TYPE OF REPORTING PERSON OO

*See Item 3.

This Amendment No. 10 amends and supplements the statement on Schedule 13D, filed on March 31, 2009, as amended (the “Schedule 13D”), by New Mountain Partners II, L.P., New Mountain Affiliated Investors II, L.P., Allegheny New Mountain Partners, L.P., New Mountain Investments II, L.L.C., New Mountain Capital, L.L.C., Steven B. Klinsky, Kathleen deLaski, Edward Grubb, the Dana Nancy deLaski Irrevocable Trust, the Daphne Jean deLaski Irrevocable Trust, the Onae Trust, and Alvaro Pascotto, with respect to the common stock, par value $0.001 per share (“Common Stock”), of Deltek, Inc., a Delaware corporation (the “Issuer” or the “Company”). Capitalized terms used herein but not defined shall have the meanings ascribed thereto in the Schedule 13D. Except as herein amended or supplemented, all other information in the Schedule 13D is as set forth therein.

ITEM 4. PURPOSE OF TRANSACTION

On October 10, 2012, the Company consummated the merger (the “Merger”) contemplated by the Agreement and Plan of Merger, by and among Project Diamond Holdings Corporation, a Delaware corporation (“Parent”), Project Diamond Merger Corp., a Delaware corporation and a wholly owned subsidiary of Parent (“Merger Sub”) and the Company. In the Merger, the Company became a subsidiary of Parent and (i) each issued and outstanding share of Common Stock (other than shares owned by the Company, Parent or Merger Sub and shares owned by stockholders who perfected appraisal rights under Section 262 of the Delaware General Corporation Law) was converted into the right to receive $13.00 in cash, without interest (the “Merger Consideration”) and (ii) each outstanding option under any Company stock option or equity incentive plan, whether or not then vested and exercisable, was cancelled and converted into the right to receive, for each share of Common Stock subject to such stock option, an amount in cash, without interest, equal to the excess, if any, of the Merger Consideration over the per share exercise price of such option. As a result of the Merger, the Reporting Persons no longer beneficially own any shares of Common Stock.

ITEM 5. INTEREST IN SECURITIES OF THE ISSUER

Items 5(a), 5(b), 5(c) and 5(e) of the Schedule 13D are hereby amended and restated in their entirety as follows:

(a) – (b) As a result of the Merger, none of the Reporting Persons may be deemed to beneficially own any shares of Common Stock or have the power to vote or dispose of any shares of Common Stock.

(c) Except as described herein, none of the Reporting Persons disposed of, or became the beneficial owner of, any shares of Common Stock during the past 60 days.

(e) The Reporting Persons ceased to be the beneficial owners of more than five percent of the Common Stock on October 10, 2012.

ITEM 6. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO SECURITIES OF THE ISSUER

See response to Item 4.

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: October 12, 2012

NEW MOUNTAIN INVESTMENTS II, L.L.C.

By:	/s/ Steven B. Klinsky
	Name:	Steven B. Klinsky
	Title:	Managing Member

NEW MOUNTAIN PARTNERS II, L.P.

By:	/s/ Steven B. Klinsky
	Name:	Steven B. Klinsky
	Title:	Managing Member of the GP of
		New Mountain Partners II, L.P.

NEW MOUNTAIN AFFILIATED INVESTORS II, L.P.

By:	/s/ Steven B. Klinsky
	Name:	Steven B. Klinsky
	Title:	Managing Member of the GP of
		New Mountain Affiliated Investors II, L.P.

ALLEGHENY NEW MOUNTAIN PARTNERS, L.P.

By:	/s/ Steven B. Klinsky
	Name:	Steven B. Klinsky
	Title:	Managing Member of the GP of
		Allegheny New Mountain Partners, L.P.

NEW MOUNTAIN CAPITAL, L.L.C.

By:	/s/ Steven B. Klinsky
	Name:	Steven B. Klinsky
	Title:	Chief Executive Officer

	/s/ Steven B. Klinsky
	STEVEN B. KLINSKY

KATHLEEN DELASKI

By:	/s/ Salman Ahmad
	Name:	Salman Ahmad
	Title:	Attorney-in-Fact (1)

EDWARD GRUBB

By:	/s/ Salman Ahmad
	Name:	Salman Ahmad
	Title:	Attorney-in-Fact (1)

THE ONAE TRUST

By:	/s/ Robert E. Gregg
	Name:	Robert E. Gregg
	Title:	Attorney-in-Fact (2)

ALVARO PASCOTTO

By:	/s/ Robert E. Gregg
	Name:	Robert E. Gregg
	Title:	Attorney-in-Fact (2)

THE DAPHNE JEAN DELASKI IRREVOCABLE TRUST

By:	/s/ Robert E. Gregg
	Name:	Robert E. Gregg
	Title:	Attorney-in-Fact (2)

THE DANA NANCY DELASKI IRREVOCABLE TRUST

By:	/s/ Robert E. Gregg
	Name:	Robert E. Gregg
	Title:	Attorney-in-Fact (2)

(1)

A Power of Attorney authorizing Salman Ahmad to act on behalf of the Reporting Person has previously been filed with the Commission.

(2)

A Power of Attorney authorizing Robert E. Gregg to act on behalf of the Reporting Person has previously been filed with the Commission.

DELTEK, INC SC 13D/A