Sec Form 4 Filing - BROWN BROTHERS HARRIMAN & CO @ DELTEK, INC - 2012-09-25

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person BROWN BROTHERS HARRIMAN & CO 2. Issuer Name and Ticker or Trading Symbol DELTEK, INC [ PROJ] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 140 BROADWAY 3. Date of Earliest Transaction (MM/DD/YY) 09/25/2012 (Street) NEW YORK, NY10005 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 09/25/2012 S 2,741,236 D $ 13.13 6,661,784 I See footnote ( 1 ) Common Stock ( 1 ) 09/26/2012 S 2,700 D $ 13.0839 6,659,084 I See footnote ( 1 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other BROWN BROTHERS HARRIMAN & CO 140 BROADWAY NEW YORK, NY10005 X 1818 Master Partners, Ltd. 140 BROADWAY NEW YORK, NY10005 X Witmer Richard H. 140 BROADWAY NEW YORK, NY10005 X Hartch Timothy E. 140 BROADWAY NEW YORK, NY10005 X Signatures /s/ Richard H. Witmer, Director, 1818 Master Partners, Ltd. 09/27/2012 Signature of Reporting Person Date /s/ Richard H. Witmer, Partner, Brown Brothers Harriman & Co. 09/27/2012 Signature of Reporting Person Date /s/ Timothy E. Hartch, Partner, Brown Brothers Harriman & Co. 09/27/2012 Signature of Reporting Person Date

Explanation of Responses:

( 1 )All shares reported on this Form 4 are held by 1818 Master Partners, Ltd. (the "Fund") on behalf of investors in the Fund. Brown Brothers Harriman & Co. ("BBH&Co."), which holds the voting interest (management shares) in the Fund, has designated Richard H. Witmer and Timothy E. Hartch, or either of them, as the sole and exclusive persons at BBH&Co. having voting power (including the power to vote or to direct the vote) and investment power (including the power to dispose or to direct the disposition) with respect to all investments of the Fund. Each reporting person disclaims beneficial ownership of the reported securities except to the extent of its or his pecuniary interest therein.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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