Exhibit 32.1

                                 CERTIFICATION
                                      OF
                       WAUSAU-MOSINEE PAPER CORPORATION
                UNDER SECTION 906 OF SARBANES-OXLEY ACT OF 2002


      The undersigned Chief Executive Officer and Chief Financial Officer of
Wausau-Mosinee Paper Corporation (the "Company") certify, pursuant to Section
906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C. Section 1350, that (1) the
Annual Report on Form 10-K of the Company for the fiscal year ended December
31, 2003 (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 operation of the Company.

      Date: March 15, 2004

                                           THOMAS J. HOWATT
                                           Thomas J. Howatt
                                           President and CEO


                                           SCOTT P. DOESCHER
                                           Scott P. Doescher
                                           Senior Vice President, Finance
                                           (Chief Financial Officer)


This certification accompanies this Annual Report on Form 10-K for the year
ended December 31, 2003, pursuant to Section 906 of the Sarbanes Oxley Act of
2002 and shall not be deemed filed by Wausau-Mosinee Paper Corporation for
purposes of the Securities Exchange Act of 1934.