Section 906 Certifications CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 Name of Issuer: VANGUARD WINDSOR FUNDS In connection with the Report on Form N-CSR of the above-named issuer that is accompanied by this certification, the undersigned hereby certifies, to his knowledge, 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 materials respects, the financial condition and results of operations of the issuer. Date: June 16, 2003 /s/ John J. Brennan ----------------------- John J. Brennan Chief Executive Officer Section 906 Certifications CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 Name of Issuer: VANGUARD WINDSOR FUNDS In connection with the Report on Form N-CSR of the above-named issuer is accompanied by this certification, the undersigned hereby certifies, to his knowledge, 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 materials respects, the financial condition and results of operations of the issuer. Date: June 16, 2003 /s/ Thomas J. Higgins ------------------------- Thomas J. Higgins Treasurer