Old Second Bancorp (OSBC) 10-Q 2003 Q2 Quarterly report

Exhibit 32.2

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Old Second Bancorp, Inc. (the “Company”) on Form 10-Q for the period ending June 30, 2003 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, J. Douglas Cheatham, Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that:

(1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Company.

/s/ J. Douglas Cheatham

J. Douglas Cheatham

Chief Financial Officer

August 12, 2003

A signed original of this written statement required by Section 906 has been provided to Old Second Bancorp, Inc. and will be retained by Old Second Bancorp, Inc. and furnished to the Securities and Exchange Commission or its staff upon request.

1