As filed with the Securities and Exchange Commission on April 22, 2005

     Approximate date of commencement of proposed sale to public: Not Applicable

     If the only securities being registered on this form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. o

     If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, please check the following box. o

     If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

     If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

     If delivery of the prospectus is expected to be made pursuant to Rule 434, please check the following box. o

          This Post-Effective Amendment No. 1 to Form S-3 shall become effective in accordance with Section 8(c) of the Securities act of 1933, as amended, on such a date as the Commission, acting pursuant to Section 8(c), may determine.

DEREGISTRATION OF SECURITIES

     On August 27, 2003, Union Planters Corporation (the “Registrant”) registered, pursuant to a registration statement on Form S-3, Registration Statement No. 333-108263 (the “Registration Statement”), $1,500,000,000 aggregate principal amount of the Registrant’s (i) senior debt securities, (ii) subordinated debt securities, (iii) preferred stock, (iv) depositary shares, (v) common stock, (vi) warrants, (vii) stock purchase contracts, and (viii) units (“Registered Securities”). The Registration Statement was amended prior to effectiveness on September 9, 2003.

     On July 1, 2004, the Registrant and Regions Financial Corporation (Central Index Key 0000036032) merged into New Regions Financial Corporation (Central Index Key 0001281761) (the “Successor Company”), and the Successor Company changed its name to Regions Financial Corporation immediately following the merger.

     As successor to the Registrant of the Registration Statement, the Successor Company is filing this Post-Effective Amendment No. 1 (the “Amendment”) to the Registration Statement to deregister the $1,000,000,000 amount of Registered Securities that represent the balance of unissued Registered Securities under the Registration Statement and none of such $1,000,000,000 Registered Securities to be deregistered have been sold as of the date this Amendment is filed.

SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing this Post-Effective Amendment No. 1 to Form S-3 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Birmingham, and the State of Alabama, on the 22nd day of April, 2005.

     Pursuant to the requirements of the Securities Act of 1933, this Registration Statement or amendment has been signed by the following persons in the capacities and on the dates indicated.