CUSIP No.  24785A108

1. NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

BROWN BROTHERS HARRIMAN & CO.
13-4973745

2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

(a) [ ]
(b) [ ]

3. SEC USE ONLY

4. CITIZENSHIP OR PLACE OF ORGANIZATION


U. S. A.

5. SOLE VOTING POWER

N/A

6. SHARED VOTING POWER

735300

7. SOLE DISPOSITIVE POWER

N/A

8. SHARED DISPOSITIVE POWER

735300

9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

735300

10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW(9) EXCLUDES CERTAIN SHARES*

[ ]

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW [9]

4.7%

12. TYPE OF REPORTING PERSON*

BK



Item 1 (a). Name of Issuer:

Deltek Systems Inc.

Item 1 (b). Address of issuer's principal executive offices:

8280 Greensboro Dr.
McLean,  VA  22102

Item 2 (a). Name of person filing:

Brown Brothers Harriman & Co.

Item 2(b). Address of principal business office:

59 Wall Street
New York City, NY 10005

Item 2(c). Citizenship:

U.S.A.

Item 2(d). Title of class of securities:

Common

Item 2(e). CUSIP Number:

24785A108

Item 3. If this statement is filed pursuant to Rules 13d-1(b) or 13d-
2(b), check whether the person filing is a:

(b)  /_X /  Bank as defined in Section 3(a)(6) of the Act.

(g) / _ /  Parent holding company, in accordance with Subsection 240
13d-1(b)(ii)(G).

Item 4. Ownership:

	(a)	Amount beneficially owned:

		735300

	(b)	Percent of class:

		4.7%

	(c)	Number of shares as to which such person has:

		(i)	Sole power to vote or to direct the vote

			N/A

(ii)	Shared power to vote or to direct the vote

			735300

(iii)	Sole power to dispose or to direct the disposition of

			N/A

(iv)	Shared power to dispose or to direct the disposition
of

			735300


Item 5. Ownership of 5 Percent or Less of a Class

yes

Item 6. Ownership of More than 5 Percent on Behalf of Another Person

N/A

Item 7. Identification and Classification of the Subsidiary
        Which Acquired the Security Being Reported on By the Parent
        Holding Company

N/A

AGREEMENT

The undersigned hereby agree to file jointly the attached statement or
amendment on Schedule 13G and any further amendments thereto pursuant to
Regulation 13G promulgated by the Securities and Exchange Commission
under the Securities Exchange Act of 1934.   Such filing shall be made
by Brown Brothers Harriman & Co. on its behalf and on behalf of the
other parties hereto.


Item 8. Identification and Classification of Members of the Group

N/A

Item 9. Notice of Dissolution of Group
N/A

Item 10. Certification

By signing below, I certify that, to the best of my knowledge and
belief, the securities referred to above were acquired in the ordinary
course of business and were not acquired for the purposes of and do not
have the effect of changing or influencing the control of the issuer of
such securities and were not acquired in connection with or as a
participant in any transaction having such purpose of effect.

Disclaimer of Beneficial Ownership

The undersigned expressly declare that the filing of this Schedule 13G
shall not be construed as an admission that the undersigned are, for
purpose of Sections 13(d) and 13(g) of the Securities Exchange Act of
1934,the beneficial owners of any securities covered by this Schedule
13G.

Signature

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.

Dated: Jan. 18, 2001
BROWN BROTHERS HARRIMAN & CO.
By:   Richard Stork
      Compliance Officer