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                                                      Registration No. 333-39267


                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D. C. 20549

                         ------------------------------
                         Post Effective Amendment No. 1
                                       TO
                                    FORM S-4

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

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                          THE COLONIAL BANCGROUP, INC.

             (Exact name of Registrant as specified in its charter)

       Delaware                         6711                    63-0661573
(State of Incorporation)   (Primary Standard Industrial      (I.R.S. Employer
                            Classification Code Number)     Identification No.)

    One Commerce Street, Suite 800                             (334) 240-5000
      Montgomery, Alabama 36104                                (Telephone No.)
(Address of principal executive offices)

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                               William A. McCrary
                                    Secretary
                              Post Office Box 1108
                            Montgomery, Alabama 36101
                     (Name and address of agent for service)

                                   Copies to:

                                Willard H. Henson
                         Miller, Hamilton, Snider & Odom
                         One Commerce Street, Suite 305
                            Montgomery, Alabama 36104

            Approximate date of commencement of proposed sale to the
           public: As soon as practicable after the effective date of
                          this Registration Statement.

         If the securities being registered on this Form are being offered in
connection with the formation of a holding company and there is compliance with
General Instruction G, check the following box. [ ]


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         The Colonial BancGroup, Inc. ("BancGroup") registered 1,147,026 shares
of its Common Stock on Form S-4, registration no. 333-39267, in connection with
the acquisition of First Central Bank ("First Central"), a Florida
state-chartered commercial bank, including shares of BancGroup Common Stock to
be issued pursuant to the exercise of options of First Central following the
merger. Such registration was declared effective on December 29, 1997.

         A total of 688,684 shares were issued in the merger on February 11,
1998 and 62,033 shares were issued upon the exercise of options of First Central
following the merger. Subsequent to the merger, BancGroup issued a 2 for 1 stock
split, effected in the form of a 100% stock dividend (the "Stock Split"). In
accordance with SEC Rule 416(b), the registration statement is deemed to cover
the additional shares resulting from the Stock Split. Accordingly, the Form S-4,
registration no. 333-39267, is deemed to register a total of 2,294,052 shares
of BancGroup common stock. Giving effect to the Stock Split, a total of
1,501,434 shares would be deemed to have been issued in the merger and pursuant
to the exercise of options after the merger. Pursuant to the undertaking given
by BancGroup in such registration statement in accordance with Regulation S-K,
item 512(a)(3), BancGroup hereby removes 792,618 shares from registration, which
represents the number of shares registered less the number of shares issued in
the merger and the number of shares issued pursuant to First Central options
after the merger.

                                    SIGNATURE

         Pursuant to Regulation S-K, item 512(a)(3) and SEC Rule 478(a)(4), the
undersigned registrant hereby executes this post effective amendment to its
registration statement on Form S-4 to remove from registration certain shares
not issued and has caused this registration statement to be signed on its behalf
by the undersigned, thereunto duly authorized, in the City of Montgomery,
Alabama, on the 2nd day of February, 2001.


                                    THE COLONIAL BANCGROUP, INC.

                                    By: /s/ W. Flake Oakley, IV
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                                       W. Flake Oakley, IV
                                       Chief Financial Officer and
                                       duly authorized agent for
                                       service