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                                                             Exhibit 99.Cert.906

FORM N-CSR ITEM 10(b) EXHIBIT

                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

            The undersigned hereby certify in their capacity as Treasurer and
President, respectively, of EATON VANCE MUTUAL FUNDS TRUST (the "Trust") (on
behalf of Eaton Vance Low Duration Fund), that:

   (a)   the Annual Report of the Trust (on behalf of Eaton Vance Low Duration
         Fund) on Form N-CSR for the period 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, as amended; and

   (b)   the information contained in the Report fairly presents, in all
         material respects, the financial condition and the results of
         operations of the Trust (on behalf of Eaton Vance Low Duration Fund)
         for such period.

A SIGNED ORIGINAL OF THIS WRITTEN STATEMENT REQUIRED BY SECTION 906 HAS BEEN
PROVIDED TO THE TRUST AND WILL BE RETAINED BY THE TRUST AND FURNISHED TO THE
SECURITIES AND EXCHANGE COMMISSION OR ITS STAFF UPON REQUEST.

EATON VANCE MUTUAL FUNDS TRUST (On behalf of Eaton Vance Low Duration Fund)

Date: February 11, 2004
      -----------------

 /s/ James L. O'Connor
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James L. O'Connor
Treasurer

Date: February 11, 2004
      -----------------


  /s/ Thomas E. Faust Jr.
- -------------------------------------------
Thomas E. Faust Jr.
President