FORM 4

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

(Print or Type Responses)

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

OMB APPROVAL

OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden
hours per response. . . 0.5

 1. Name and Address of Reporting Person *

(Last)            (First)              (Middle)

(Street)

(City)       (State)          (Zip)

 2. Issuer Name and Ticker
    or Trading Symbol

SI International, Inc. (SINT)

 3. I.R.S. Identification
    Number of Reporting
    Person, if an entity
    (voluntary)

 4. Statement for
 Month/Day/Year

2/21/03

 5. If Amendment, Date of
   Original (Month/Day/Year)

 6. Relationship of Reporting Person(s) to Issuer

(Check all applicable)

      Director

  X  Officer (give title below)

      10% Owner

      Other (specify below)

President and Chief Operating Officer

 7. Individual or Joint/Group
     Filing (Check Applicable Line)

  X  Form filed by One Reporting Person

      Form filed by More than One Reporting Person

1. Title of Security
(Instr. 3)

2. Transaction Date (Month/Day/
Year)

2A. Deemed Execution Date, if any (Month/Day/
Year)

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

2/21/03

P

200

A

$8.35

D

Common Stock

2/21/03

P

400

A

$8.37

D

Common Stock

2/21/03

P

200

A

$8.32

D

Common Stock

2/21/03

P

200

A

$8.28

D

Common Stock

2/21/03

P

500

A

$8.26

D

Common Stock

2/21/03

P

1,000

A

$8.24

D

Common Stock

2/21/03

P

500

A

$8.18

D

Common Stock

2/21/03

P

500

A

$8.23

D

Common Stock

2/21/03

P

500

A

$8.25

24,676

D

Common Stock

2/21/03

P

200

A

$8.26

I

(1)

Common Stock

2/21/03

P

200

A

$8.22

400

I

(2)

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
(Month/Day/
Year)

3A. Deemed Execution Date, if any (Month/Day/
Year)

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
(Month/Day/Year)

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 Securities: 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

Explanation of Responses:

(1)  By self as custodian for daughter under Uniform Gifts to Minors Act.

(2)  By self as custodian for daughter under Uniform Gifts to Minors Act.

** Signature of Reporting Person

Date