N-CSR Item 12(a)(2) - Exhibits: Certifications


I, John B. Fisher, certify that:

   1.  I have reviewed this report on Form N-CSR of Federated Short-Term
       Municipal Trust ("registrant");

   2.  Based on my knowledge, this report does not contain any untrue statement
       of a material fact or omit to state a material fact necessary to make the
       statements made, in light of the circumstances under which such
       statements were made, not misleading with respect to the period covered
       by this report;

   3.  Based on my knowledge, the financial statements, and other financial
       information included in this report, fairly present in all material
       respects the financial condition, results of operations, changes in net
       assets, and cash flows (if the financial statements are required to
       include a statement of cash flows) of the registrant as of, and for, the
       periods presented in this report;

   4.  The registrant's other certifying officers and I are responsible for
       establishing and maintaining disclosure controls and procedures (as
       defined in rule 30a-3(c) under the Investment Company Act of 1940) and
       internal control over financial reporting (as defined in Rule 30a-3(d)
       under the Investment Company Act of 1940) for the registrant and have:

          a. designed such disclosure controls and procedures, or caused such
             disclosure controls and procedures to be designed under our
             supervision, to ensure that material information relating to the
             registrant, including its consolidated subsidiaries, is made known
             to us by others within those entities, particularly during the
             period in which this report is being prepared;

          b. designed such internal control over financial reporting, or caused
             such internal control over financial reporting to be designed under
             our supervision, to provide reasonable assurance regarding the
             reliability of financial reporting and the preparation of financial
             statements for external purposes in accordance with generally
             accepted accounting principles;

          c. evaluated the effectiveness of the registrant's disclosure controls
             and procedures and presented in this report our conclusions about
             the effectiveness of the disclosure controls and procedures, as of
             a date within 90 days prior to the filing date of this report based
             on such evaluation; and

          d. disclosed in this report any change in the registrant's internal
             control over financial reporting that occurred during the second
             fiscal quarter of the period covered by this report that has
             materially affected, or is reasonably likely to materially affect,
             the registrant's internal control over financial reporting; and

   5.  The registrant's other certifying officers and I have disclosed to the
       registrant's auditors and the audit committee of the registrant's board
       of directors (or persons performing the equivalent functions):

          a. all significant deficiencies and material weaknesses in the design
             or operation of internal control over financial reporting which are
             reasonably likely to adversely affect the registrant's ability to
             record, process, summarize, and report financial information; and

          b. any fraud, whether or not material, that involves management or
             other employees who have a significant role in the registrant's
             internal control over financial reporting.




Date: February 14, 2007
/S/ John B. Fisher
John B. Fisher
President - Principal Executive Officer






   N-CSR Item 12(a)(2) - Exhibits: Certifications


I, Richard A. Novak, certify that:

   1.  I have reviewed this report on Form N-CSR of Federated Short-Term
       Municipal Trust ("registrant");

   2.  Based on my knowledge, this report does not contain any untrue statement
       of a material fact or omit to state a material fact necessary to make the
       statements made, in light of the circumstances under which such
       statements were made, not misleading with respect to the period covered
       by this report;

   3.  Based on my knowledge, the financial statements, and other financial
       information included in this report, fairly present in all material
       respects the financial condition, results of operations, changes in net
       assets, and cash flows (if the financial statements are required to
       include a statement of cash flows) of the registrant as of, and for, the
       periods presented in this report;

   4.  The registrant's other certifying officers and I are responsible for
       establishing and maintaining disclosure controls and procedures (as
       defined in rule 30a-3(c) under the Investment Company Act of 1940) and
       internal control over financial reporting (as defined in Rule 30a-3(d)
       under the Investment Company Act of 1940) for the registrant and have:

          a. designed such disclosure controls and procedures, or caused such
             disclosure controls and procedures to be designed under our
             supervision, to ensure that material information relating to the
             registrant, including its consolidated subsidiaries, is made known
             to us by others within those entities, particularly during the
             period in which this report is being prepared;

          b. designed such internal control over financial reporting, or caused
             such internal control over financial reporting to be designed under
             our supervision, to provide reasonable assurance regarding the
             reliability of financial reporting and the preparation of financial
             statements for external purposes in accordance with generally
             accepted accounting principles;

          c. evaluated the effectiveness of the registrant's disclosure controls
             and procedures and presented in this report our conclusions about
             the effectiveness of the disclosure controls and procedures, as of
             a date within 90 days prior to the filing date of this report based
             on such evaluation; and

          d. disclosed in this report any change in the registrant's internal
             control over financial reporting that occurred during the second
             fiscal quarter of the period covered by this report that has
             materially affected, or is reasonably likely to materially affect,
             the registrant's internal control over financial reporting; and

   5.  The registrant's other certifying officers and I have disclosed to the
       registrant's auditors and the audit committee of the registrant's board
       of directors (or persons performing the equivalent functions):

          a. all significant deficiencies and material weaknesses in the design
             or operation of internal control over financial reporting which are
             reasonably likely to adversely affect the registrant's ability to
             record, process, summarize, and report financial information; and

          b. any fraud, whether or not material, that involves management or
             other employees who have a significant role in the registrant's
             internal control over financial reporting.




Date: February 14, 2007
/S/ Richard A. Novak
Richard A. Novak
Treasurer, Principal Financial Officer