EXHIBIT 31(b) CFO CERTIFICATION PURSUANT TO RULE 13a-14(a)/15d-14(a) I, John W. Conlon, certify that: 1. I have reviewed this Quarterly Report on Form 10-Q of Peoples Bancorp Inc.; 2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report; Date: August 14, 2003 /s/ JOHN W. CONLON ------------------------------------- John W. Conlon Chief Financial Officer and Treasurer (Principal Financial Officer)