The Trustees of Federated MDT Series

5800 Corporate Drive

Pittsburgh, PA  15237-7000

      Re:  Legality of Shares Opinion

Ladies and Gentlemen:

      Federated MDT Large Cap Growth Fund ("Acquiring Fund"), a portfolio of
Federated MDT Series (the "Trust"), proposes to acquire the assets of Federated
Large Cap Growth Fund ("Acquired Fund"), a portfolio of Federated Equity Funds,
in exchange for Class A, Class B and Class C Shares of the Acquiring Fund
("Shares") pursuant to the Agreement and Plan of Reorganization dated May 1,
2007 ("Agreement"), included as an exhibit to the registration statement of the
Trust filed on Form N-14 (Securities Act Registration No. 333-141939) under the
Securities Act of 1933, as amended (the "N-14 Registration Statement").

      As counsel we have reviewed the appropriate documents relating to the
organization of the Trust, its registration under the Investment Company Act of
1940 and the registration of its securities on Form N-1A under the Securities
Act of 1933 and participated in the drafting of the N-14 Registration Statement.
Specifically, we have examined and are familiar with the Declaration of Trust
and Bylaws of the Trust, and such other documents and records as we deemed
relevant for the purpose of rendering this opinion.  We have also reviewed
questions of law as deemed necessary or appropriate by us for the purposes of
this opinion.

      Based upon the foregoing, we are of the opinion that:

      1.  The Trust is duly organized and validly existing pursuant to its
Declaration of Trust.

      2.  The Shares, when issued pursuant to the Agreement, will be legally and
validly issued in accordance with the Declaration of Trust.  Such Shares, when
so issued, will be fully paid and non-assessable.

      We hereby consent to the filing of this opinion as an exhibit to the N-14
Registration Statement referred to above and to any application or registration
statement filed under the securities laws of any of the States of the United
States.

                                              Yours truly,

                                              Reed Smith LLP