FEDERATED MDT SERIES

                           Federated Investors Funds
                              5800 Corporate Drive
                      Pittsburgh, Pennsylvania 15237-7000

                                  July 20, 2007


EDGAR Operations Branch
U.S. Securities and Exchange Commission
Division of Investment Management
100 F Street, N.E.
Washington, DC  20549-4720


     RE:  Form N-14
          FEDERATED MDT SERIES
          Federated MDT Balanced Fund ("Portfolio")
          1933 Act File No. 333-134468

Dear Sir or Madam:

       Transmitted  herewith  for filing pursuant to the Securities Act of 1933,
as  amended,  ("1933 Act"), is the  Registration  Statement  on  Form  N-14  for
Federated MDT Series ("Trust").

       The purpose  of  this  Registration  Statement  is  to register shares of
beneficial  interest  of  the  above-named Portfolio under the 1933  Act.  These
shares are being registered pursuant  to an Agreement and Plan of Reorganization
pursuant to which Federated Conservative  Allocation  Fund,  Federated  Moderate
Allocation  Fund,  and Federated Growth Allocation Fund, portfolios of Federated
Managed Allocation Portfolios  will  transfer substantially all of its assets to
the Portfolio in exchange for shares of the Portfolio.

       In connection with the review of  this  filing by staff of the Securities
and Exchange Commission, the Fund acknowledges the  staff's  view that: the Fund
is responsible for the adequacy and accuracy of the disclosure  in  the filings;
staff  comments  or changes to disclosure in response to staff comments  in  the
filings reviewed by  the  staff  do not foreclose the Commission from taking any
action with respect to the filing; and the Fund may not assert staff comments as
a defense in any proceeding initiated  by the Commission or any person under the
federal securities laws of the United States.






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We would appreciate receiving any comments  you may have by August  10, 2007. If
you  have any questions on the enclosed material,  please  do  not  hesitate  to
contact me at (412) 288-6659.

                                                     Very truly yours,



                                                     /s/ Joseph W. Kulbacki
                                                     Joseph W. Kulbacki
                                                     Paralegal

Enclosures