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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 Investment Trust (the "Trust") (on
behalf of Eaton Vance National Limited Fund), that:

 (a)  the Semi-Annual Report of the Trust (on behalf of Eaton Vance National
      Limited Fund) on Form N-CSR for the period ended September 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 National Limited 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 Investment Trust (On behalf of Eaton Vance National Limited Fund)

Date: November 18, 2003
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/s/ James L. O'Connor
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James L. O'Connor
Treasurer

Date: November 18, 2003
      -----------------


/s/ Thomas J. Fetter
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Thomas J. Fetter
President