<PAGE>

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C., 20549

                               ----------------

                                  FORM 10-K/A

                      Amendment To Application or Report
                 Filed Pursuant To Section 12, 13 Or 15(d) of
                      The Securities Exchange Act Of 1934

                               ----------------

                             BELLSOUTH CORPORATION

                                AMENDMENT No. 1

The undersigned registrant hereby amends the following items, financial
statements, exhibits or other portions of its Annual Report on Form 10-K for the
year ended December 31, 1999 as set forth in the pages attached hereto:

Item 14a(3) Exhibits:

99a Financial Statements for BellSouth Retirement Savings Plan for the year
ended December 31, 1999.

99b Financial Statements for BellSouth Savings and Security Plan for the year
ended December 31, 1999.

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Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this amendment to be signed on its behalf by the
undersigned, thereunto duly authorized.

                                 BellSouth Corporation


                                 By: /s/ Ronald M. Dykes
                                     ----------------------------
                                     Ronald M. Dykes
                                     Chief Financial Officer
                                     June 26, 2000
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   (3) Exhibits: (As filed with Form 10-K as of 12/31/99, unless otherwise
       noted)

EXHIBIT
NUMBER
-------

  3a   Amended Articles of Incorporation of BellSouth Corporation effective
       December 11, 1999.
  3b   Bylaws of BellSouth Corporation as Amended on November 23, 1998.
  4    BellSouth Corporation Shareholder Rights Agreement. (Exhibit 1 to Report
       on Form 8-A dated November 23, 1999, File No. 1-8607.)
  4a   No instrument which defines the rights of holders of long and
       intermediate term debt of BellSouth Corporation is filed herewith
       pursuant to Regulation S-K, Item 601(b)(4)(iii)(A). Pursuant to this
       regulation, BellSouth Corporation hereby agrees to furnish a copy of any
       such instrument to the SEC upon request.
 10a   BellSouth Corporation Officer Short Term Incentive Award Plan.
       (Exhibit 10y to Form 10-Q for the quarter ended September 30, 1996,
       File No. 1-8607.)
 10b   BellSouth Corporation Executive Long Term Incentive Plan. (Exhibit 10e
       to Form 10-K for the year ended December 31, 1991, File No. 1-8607.)
 10c   BellSouth Corporation Executive Long Term Disability and Survivor
       Protection Plan as amended and restated effective January 1, 1994.
       (Exhibit 10c-1 to Form 10-K for the year ended December 31, 1993, File
       No. 1-860 7.)
 10d   BellSouth Corporation Executive Transfer Plan. (Exhibit 10ee to
       Registration Statement No. 2-87846.)
 10e   BellSouth Corporation Death Benefit Program. (Exhibit 10ff to Form 10-K
       for the year ended December 31, 1989, File No. 1-8607.)
 10f   BellSouth Corporation Plan For Non-Employee Directors' Travel Accident
       Insurance. (Exhibit 10ii to Registration Statement No. 2-87846.)
 10g   BellSouth Corporation Executive Incentive Award Deferral Plan as amended
       and restated effective September 23, 1996. (Exhibit 10g to Form 10-K for
       the year ended December 31, 1996, File No. 1-8607.)
 10h   BellSouth Corporation Nonqualified Deferred Compensation Plan as amended
       and restated effective November 25, 1996. (Exhibit 10h to Form 10-K for
       the year ended December 31, 1996, File No. 1-8607.)
 10i   BellSouth Corporation Supplemental Executive Retirement Plan as amended
       on March 23, 1998. (Exhibit 10i to Form 10-Q for the quarter ended March
       31, 1998, File No. 1-8607.)
 10j   BellSouth Corporation Directors Retirement Plan. (Exhibit 10qq to Form
       10-K for the year ended December 31, 1986, File No. 1-8607.)
 10k   BellSouth Corporation Financial Counseling Plan. (Exhibit 10r to Form
       10-K for the year ended December 31, 1992, File No. 1-8607.)
 10k-1 Amendment dated November 3, 1995 to the BellSouth Corporation Financial
       Counseling Plan for Executives. (Exhibit 10l-1 to Form 10-K for the year
       ended December 31, 1995, File No. 1-8607.)
 10l   BellSouth Corporation Deferred Compensation Plan for Non-Employee
       Directors. (Exhibit 10gg to Registration Statement No. 2-87846.)
 10m   BellSouth Corporation Executive Life Insurance Plan as amended and
       restated as the BellSouth Split-Dollar Life Insurance Plan, effective
       August 31, 1998. (Exhibit 10m to Form 10-K for the year ended December
       31, 1998, File No. 1-8607.)
 10n   BellSouth Corporation Non-Employee Director Stock Plan. (Exhibit 10z to
       Form 10-Q for the quarter ended March 31, 1997, File No. 1-8607.)
 10p   BellSouth Non-Employee Directors Charitable Contribution Program.
       (Exhibit 10z to Form 10-K for the year ended December 31, 1992, File No.
       1-8607.)
 10q   BellSouth Personal Retirement Account Pension Plan, as amended and
       restated effective January 1, 1998. (Exhibit 10q to Form 10-K for the
       year ended December 31, 1998, File No. 1-8607)
 10q-1 Amendment dated December 22, 1998 to the BellSouth Personal Retirement
       Account Pension Plan. (Exhibit 10q-1 to Form 10-K for the year ended
       December 31, 1998, File No. 1-8607.)
 10q-2 Amendment dated March 22, 1999 to the BellSouth Personal Retirement
       Account Pension Plan. (Exhibit 10q-2 to Form 10-Q for the quarter ended
       March 31, 1999, File No. 1-8607.)
 10q-3 Amendment dated April 7, 1999 to the BellSouth Personal Retirement
       Account Pension Plan. (Exhibit 10q-3 to Form 10-Q for the quarter ended
       March 31, 1999, File No. 1-8607.)
 10q-4 Amendment dated May 6, 1999 to the BellSouth Personal Retirement Account
       Pension Plan. (Exhibit 10q-4 to Form 10-Q for the quarter ended June 30,
       1999, File No. 1-8607.)
 10q-5 Amendment dated May 6, 1999 to the BellSouth Personal Retirement Account
       Pension Plan. (Exhibit 10q-5 to Form 10-Q for the quarter ended June 30,
       1999, File No. 1-8607.)
 10q-6 Amendment dated May 7, 1999 to the BellSouth Personal Retirement Account
       Pension Plan. (Exhibit 10q-6 to Form 10-Q for the quarter ended June 30,
       1999, File
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        No. 1-8607.)
 10q-7  Amendment dated September 13, 1999 to the BellSouth Personal Retirement
        Account Pension Plan. (Exhibit 10q-7 to Form 10-Q for the quarter ended
        September 30, 1999, File No. 1-8607.)
 10q-8  Amendment dated December 22, 1999 to the BellSouth Personal Retirement
        Account Pension Plan.
 10r    BellSouth Corporation Trust Under Executive Benefit Plan(s) as amended
        April 28, 1995. (Exhibit 10u-1 to Form 10-Q for the quarter ended June
        30, 1995, File No. 1-8607.)
 10r-1  Amendment dated May 23, 1996 to the BellSouth Corporation Trust Under
        Executive Benefit Plan(s). (Exhibit 10s-1 to Form 10-Q for the quarter
        ended June 30, 1996, File No. 1-8607.)
 10s    BellSouth Telecommunications, Inc. Trust Under Executive Benefit Plan(s)
        as amended April 28, 1995. (Exhibit 10v-1 to Form 10-Q for the quarter
        ended June 30, 1995, File No. 1-8607.)
 10s-1  Amendment dated May 23, 1996 to the BellSouth Telecommunications, Inc.
        Trust Under Executive Benefit Plan(s). (Exhibit 10t-1 to Form 10-Q for
        the quarter ended June 30, 1996, File No. 1-8607.)
 10t    BellSouth Corporation Trust Under Board of Directors Benefit Plan(s) as
        amended April 28, 1995. (Exhibit 10w-1 to Form 10-Q for the quarter
        ended June 30, 1995, File No. 1-8607.)
 10t-1  Amendment dated May 23, 1996 to the BellSouth Corporation Trust Under
        Board Directors Benefit Plan(s). (Exhibit 10u-1 to Form 10-Q for the
        quarter ended June 30, 1996, File No. 1-8607.)
 10u    BellSouth Telecommunications, Inc. Trust Under Board of Directors
        Benefit Plan(s) as amended April 28, 1995. (Exhibit 10x-1 to Form 10-Q
        for the quarter ended June 30, 1995, File No. 1-8607.)
 10u-1  Amendment dated May 23, 1996 to the BellSouth Telecommunications, Inc.
        Trust Under Board of Directors Benefit Plan(s). (Exhibit 10v-1 to Form
        10-Q for the quarter ended June 30, 1996, File No. 1-8607.)
 10v    BellSouth Corporation Stock Plan as amended on September 23, 1996 and
        November 24, 1996. (Exhibit 10v to Form 10-K for the year ended December
        31, 1996, File No. 1-8607.)
 10w    BellSouth Retirement Savings Plan as amended and restated effective July
        1, 1996. (Exhibit 10x to Form 10-Q for the quarter ended September 30,
        1996, File No. 1-8607.)
 10w-1  Amendment dated February 18, 1997 to the BellSouth Retirement Savings
        Plan. (Exhibit 10w-1 to Form 10-Q for the quarter ended March 31, 1997,
        File No. 1-8607.)
 10w-2  Amendment dated June 24, 1997 to the BellSouth Retirement Savings Plan.
        (Exhibit 10w-2 to Form 10-Q/A for the quarter ended June 30, 1997, File
        No. 1-8607.)
 10w-3  Amendment dated May 5, 1998 to the BellSouth Retirement Savings Plan.
        (Exhibit 10w-3 to Form 10-Q for the quarter ended March 31, 1998, File
        No. 1-8607.)
 10w-4  Amendment dated December 23, 1998 to the BellSouth Retirement Savings
        Plan. (Exhibit 10w-4 to Form 10-K for the year ended December 31, 1998,
        File No. 1-8607.)
 10w-5  Amendment dated December 22, 1999 to the BellSouth Retirement Savings
        Plan.
 10x    BellSouth Corporation Officer Estate Enhancement Plan and Agreement.
        (Exhibit 10x to Form 10-K for the year ended December 31, 1996, File No.
        1-8607.)
 10y    BellSouth Change in Control Executive Severance Agreements. (Exhibit
        10y to Form 10-K for the year ended December 31, 1996, File No. 1-8607.)
 10z    BellSouth Compensation Deferral Plan as amended and restated effective
        September 28, 1998. (Exhibit 10z to Form 10-Q for the quarter ended
        March 31, 1999, File No. 1-8607.)
 10aa   BellSouth Employee Stock Investment Plan. (Exhibit 10aa to Form 10-Q for
        the quarter ended March 31, 1998, File No. 1-8607.)
 10aa-1 Amendment dated November 27, 1996 to the BellSouth Employee Stock
        Investment Plan. (Exhibit 10aa-1 to Form 10-Q for the quarter ended
        March 31, 1998, File No. 1-8607.)
 10aa-2 Amendment dated March 21, 1997 to the BellSouth Employee Stock
        Investment Plan. (Exhibit 10aa-2 to Form 10-Q for the quarter ended
        March 31, 1998, File No. 1-8607.)
 10aa-3 Amendment dated May 5, 1998 to the BellSouth Employee Stock Investment
        Plan. (Exhibit 10aa-3 to Form 10-Q for the quarter ended March 31, 1998,
        File No. 1-8607.)
 10bb   BellSouth Officer Motor Vehicle Policy. (Exhibit 10bb to Form 10-Q for
        the quarter ended March 31, 1998, File No. 1-8607.)
 10cc   BellSouth Supplemental Life Insurance Plan, as amended and restated
        effective August 31, 1998. (Exhibit 10cc to Form 10-K for the year ended
        December 31, 1998, File No. 1-8607.)
 10dd   Agreement with Chief Executive Officer. (Exhibit 10dd to Form 10-K for
        the year ended December 31, 1998, File No. 1-8607.)
 10ee   Retirement Agreement dated October 27, 1999 for Jere A. Drummond.
        (Exhibit 10ee to Form 10-Q for the quarter ended September 30, 1999,
        File No. 1-8607.)
 10ff   Retirement Agreement dated December 14, 1999 for Earle Mauldin.
 11     Computation of Earnings Per Share.
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 12     Computation of Ratio of Earnings to Fixed Charges.
 21     Subsidiaries of BellSouth.
 24     Powers of Attorney.
 27     Financial Data Schedule.
 99a    Annual report on Form 11-K for BellSouth Retirement Savings Plan for
        the fiscal year ended December 31, 1999.*
 99b    Annual report on Form 11-K for BellSouth Savings and Security Plan for
        the fiscal year ended December 31, 1999.*

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*  Filed herewith