Middlefield Banc (MBCN) 10-Q 2003 Q1 Quarterly report

Exhibit 99.3

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 Middlefield Banc Corp. (the “Company”) on Form 10-Q for the period ending March 31, 2003 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), we, Thomas G. Caldwell, President ,and Donald L. Stacy, Chief Financial Officer, 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 results of operations of the Company.

/s/ THOMAS G. CALDWELL	/s/ DONALD L. STACY
Thomas G. Caldwell President	Donald L. Stacy Principal Financial and Accounting Officer

May 9, 2003

A signed original of this written statement required by Section 906 has been provided to Middlefield Banc Corp. and will be retained by Middlefield Banc Corp. and furnished to the Securities and Exchange Commission or its staff upon request.