<Page>

FORM N-CSR ITEM 10(c) 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 Variable Trust (the "Trust")
         (on behalf of Eaton Vance VT Floating-Rate Income Fund), that:

   (a)   the Semi-Annual Report of the Trust (on behalf of Eaton Vance VT
         Floating-Rate Income Fund) on Form N-CSR for the period ended June 30,
         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 VT Floating-Rate
         Income 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 Variable Trust (On behalf of Eaton Vance VT Floating-Rate Income
Fund)

Date: August 18, 2003
     ----------------


/S/ James L. O'Connor
- ---------------------
James L. O'Connor
Treasurer

Date: August 18, 2003
     ----------------


/S/ James B. Hawkes
- -------------------
James B. Hawkes
President