<Page>
Exhibit 99.Cert.906
FORM N-CSR ITEM 11(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 California Limited Maturity Municipals Fund), that:
(a) the Annual Report of the Trust (on behalf of Eaton Vance California
Limited Maturity Municipals Fund) on Form N-CSR for the period ended
March 31, 2004 (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 California Limited
Maturity Municipals 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 California Limited
Maturity Municipals Fund)
Date: May 19, 2004
------------
/S/ James L. O'Connor
- ---------------------
James L. O'Connor
Treasurer
Date: May 19, 2004
------------
/S/ Thomas J. Fetter
- --------------------
Thomas J. Fetter
President
<Page>
Exhibit 99.Cert.906
FORM N-CSR ITEM 11(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 Florida Limited Maturity Municipals Fund), that:
(a) the Annual Report of the Trust (on behalf of Eaton Vance Florida
Limited Maturity Municipals Fund) on Form N-CSR for the period ended
March 31, 2004 (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 Florida Limited
Maturity Municipals 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 Florida Limited Maturity
Municipals Fund)
Date: May 19, 2004
------------
/s/ James L. O'Connor
- ------------------------
James L. O'Connor
Treasurer
Date: May 19, 2004
------------
/s/ Thomas J. Fetter
- ------------------------
Thomas J. Fetter
President
<Page>
Exhibit 99.Cert.906
FORM N-CSR ITEM 11(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 Massachusetts Limited Maturity Municipals Fund), that:
(a) the Annual Report of the Trust (on behalf of Eaton Vance Massachusetts
Limited Maturity Municipals Fund) on Form N-CSR for the period ended
March 31, 2004 (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 Massachusetts Limited
Maturity Municipals 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 Massachusetts Limited
Maturity Municipals Fund)
Date: May 19, 2004
------------
/S/ James L. O'Connor
- ---------------------
James L. O'Connor
Treasurer
Date: May 19, 2004
------------
/S/ Thomas J. Fetter
- --------------------
Thomas J. Fetter
President
<Page>
Exhibit 99.Cert.906
FORM N-CSR ITEM 11(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 New Jersey Limited Maturity Municipals Fund), that:
(a) the Annual Report of the Trust (on behalf of Eaton Vance New Jersey
Limited Maturity Municipals Fund) on Form N-CSR for the period ended
March 31, 2004 (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 New Jersey Limited
Maturity Municipals 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 New Jersey Limited
Maturity Municipals Fund)
Date: May 19, 2004
------------
/S/ James L. O'Connor
- ---------------------
James L. O'Connor
Treasurer
Date: May 19, 2004
------------
/S/ Thomas J. Fetter
- --------------------
Thomas J. Fetter
President
<Page>
Exhibit 99.Cert.906
FORM N-CSR ITEM 11(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 New York Limited Maturity Municipals Fund), that:
(a) the Annual Report of the Trust (on behalf of Eaton Vance New York
Limited Maturity Municipals Fund) on Form N-CSR for the period ended
March 31, 2004 (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 New York Limited
Maturity Municipals 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 New York Limited
Maturity Municipals Fund)
Date: May 19, 2004
------------
/S/ James L. O'Connor
- ---------------------
James L. O'Connor
Treasurer
Date: May 19, 2004
------------
/S/ Thomas J. Fetter
- --------------------
Thomas J. Fetter
President
<Page>
Exhibit 99.Cert.906
FORM N-CSR ITEM 11(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 Ohio Limited Maturity Municipals Fund), that:
(a) the Annual Report of the Trust (on behalf of Eaton Vance Ohio Limited
Maturity Municipals Fund) on Form N-CSR for the period ended March 31,
2004 (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 Ohio Limited Maturity
Municipals 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 Ohio Limited Maturity
Municipals Fund)
Date: May 19, 2004
------------
/S/ James L. O'Connor
- ---------------------
James L. O'Connor
Treasurer
Date: May 19, 2004
------------
/S/ Thomas J. Fetter
- --------------------
Thomas J. Fetter
President
<Page>
Exhibit 99.Cert.906
FORM N-CSR ITEM 11(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 Pennsylvania Limited Maturity Municipals Fund), that:
(a) the Annual Report of the Trust (on behalf of Eaton Vance Pennsylvania
Limited Maturity Municipals Fund) on Form N-CSR for the period ended
March 31, 2004 (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 Pennsylvania Limited
Maturity Municipals 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 Pennsylvania Limited
Maturity Municipals Fund)
Date: May 19, 2004
------------
/S/ James L. O'Connor
- ---------------------
James L. O'Connor
Treasurer
Date: May 19, 2004
------------
/S/ Thomas J. Fetter
- --------------------
Thomas J. Fetter
President