FEDERATED MDT SERIES Federated Investors Funds 5800 Corporate Drive Pittsburgh, Pennsylvania 15237-7000 April 5, 2007 EDGAR Operations Branch Securities and Exchange Commission Division of Investment Management 100 F Street, N.E. Washington, DC 20549 RE: FEDERATED MDT SERIES ("Registrant") FEDERATED MDT LARGE CAP GROWTH FUND 1933 Act File No. 333-134468 1940 Act File No. 811-21904 Dear Sir or Madam: On behalf of the Registrant, I hereby submit this application for withdrawal of the Registrant's Registration Statement filed on Form N-14 on April 3, 2007 wherein the Registrant was to acquire the Class A, Class B and Class C Shares of Federated Large Cap Growth Fund. This withdrawal is being made to correct a technical error that occurred during the filing of the Form N-14 Registration Statement. We therefore respectfully request, pursuant to Rule 477(a) of the Securities Act of 1933, the Securities and Exchange Commission to withdraw the filing made on April 3, 2007. If you have any questions regarding this application for withdrawal, please contact Seana Banks at (412) 288-6340. Very truly yours, /s/ Todd P. Zerega Todd P. Zerega Assistant Secretary