International Bancshares (IBOC) 10-Q 2003 Q3 Quarterly report

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of International Bancshares Corporation (the “Company”) on Form 10-Q for the period ended June 30, 2003, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Dennis E. Nixon, Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

(1)The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d), and

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

By:		/s/ Dennis E. Nixon
		Dennis E. Nixon
		President
	Date:	November 14, 2003