Exhibit 99.CERTB

Certification Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
(subsection (a) and (b) of section 1350, chapter 63 of title 18, United States
Code)

In connection with the attached Report of Allmerica Investment Trust (the
"Trust") on Form N-CSR to be filed with the Securities and Exchange Commission
for the period ended June 30, 2005 (the "Report"), each of the undersigned
officers of the Trust does hereby certify that, to the best of such officer's
knowledge:

     1.   The Report fully complies with the requirements of Section 13(a) or
          15(d) of the Securities Exchange Act of 1934; and

     2.   The information contained in the Report fairly presents, in all
          material respects, the financial condition and results of operations
          of the Trust as of, and for, the periods presented in the Report.

Dated: August 22, 2005


/s/ John P. Kavanaugh
- -----------------------------------
John P. Kavanaugh
President and Chairman
(Principal Executive Officer)

Dated: August 22, 2005


/s/ Paul S. Bellany
- -----------------------------------
Paul S. Bellany
Assistant Vice President and Treasurer
(Principal Financial Officer)