<PAGE>   1

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

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549



                                    FORM 8-K

                                 CURRENT REPORT
                       PURSUANT TO SECTION 13 OR 15(d) OF
                      THE SECURITIES EXCHANGE ACT OF 1934


        Date of Report (Date of earliest event reported): August 4, 1998

                                 WORLDCOM, INC.
             (Exact Name of Registrant as Specified in its Charter)

 Georgia                            0-11258                    58-1521612
(State or Other                  (Commission File            (IRS Employer
 Jurisdiction of                     Number)            (Identification Number)
 Incorporation)


                             515 East Amite Street
                        Jackson, Mississippi 39201-2702
                    (Address of Principal Executive Office)


Registrant's telephone number, including area code:  (601) 360-8600




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

<PAGE>   2
ITEM 5.  OTHER EVENTS.

(1) On October 1, 1997, WorldCom, Inc. ("WorldCom" or the "Company") announced
its intention to commence an exchange offer to acquire all of the outstanding
shares of MCI common stock, par value $.10 per share ("MCI Common Stock"), for
$41.50 of WorldCom Common Stock, subject to adjustment in certain circumstances
as set forth in materials filed by WorldCom with the Securities and Exchange
Commission (the "Commission"). On November 9, 1997, WorldCom entered into an
Agreement and Plan of Merger (the "MCI/WorldCom Merger Agreement") with MCI and
MCI Merger Sub, providing for the merger (the "MCI/WorldCom Merger"), with MCI
Merger Sub surviving as a wholly owned subsidiary of WorldCom. As a result of
the MCI/WorldCom Merger, the separate corporate existence of MCI will cease, and
MCI Merger Sub (which will be renamed "MCI Communications Corporation") will
succeed to all the rights and be responsible for all the obligations of MCI in
accordance with the Delaware General Corporation Law. Subject to the terms and
conditions of the MCI/WorldCom Merger Agreement, each share of MCI Common Stock
outstanding immediately prior to the effective time of the MCI/WorldCom Merger
(the "MCI/WorldCom Effective Time"), other than shares owned by WorldCom or held
by MCI, will be converted into the right to receive that number of shares of
WorldCom Common Stock equal to the MCI Exchange Ratio (as defined below), and
each share of MCI Class A common stock, par value $.10 per share ("MCI Class A
Common Stock"), outstanding immediately prior to the MCI/WorldCom Effective Time
will be converted into the right to receive $51.00 in cash, without interest
thereon. The "MCI Exchange Ratio" means the quotient (rounded to the nearest
1/10,000) determined by dividing $51.00 by the average of the high and low sales
prices of WorldCom Common Stock (the "MCI/WorldCom Average Price") as reported
on The Nasdaq National Market on each of the 20 consecutive trading days ending
with the third trading day immediately preceding the MCI/WorldCom Effective
Time; provided, however, that the MCI Exchange Ratio will not be less than
1.2439 or greater than 1.7586. Cash will be paid in lieu of the issuance of any
fractional share of WorldCom Common Stock in the MCI/WorldCom Merger.

        Based on the number of shares of MCI Common Stock outstanding as of
March 31, 1998 and assumed MCI Exchange Ratios of 1.2439 and 1.7586,
approximately 731,890,172 shares and 1,034,731,133 shares, respectively, of
WorldCom Common Stock would be issued in the MCI/WorldCom Merger. In addition,
as of March 31, 1998, outstanding options to purchase shares of MCI Common
Stock would be converted in the MCI/WorldCom Merger to options to acquire an
aggregate of approximately 103,019,687 shares and 145,647,095 shares,
respectively, of WorldCom Common Stock, and the exercise price would be
adjusted to reflect the MCI Exchange Ratio, so that, on exercise, the holders
would receive, in the aggregate, the same number of shares of WorldCom Common
Stock as they would have received had they exercised prior to the MCI/WorldCom
Merger, at the same exercise price.

        The MCI/WorldCom Merger was approved by the MCI stockholders and the
WorldCom shareholders at separate meetings held on March 11, 1998. The
MCI/WorldCom Merger was subsequently conditionally approved by the U.S.
Department of Justice and the European Commission, subject to the divestiture
of MCI's Internet services business. See Item 5(2) below. In addition, the 
MCI/WorldCom Merger is also subject to approvals from the Federal Communications
Commission ("FCC") and certain state government bodies. WorldCom anticipates
that the MCI/WorldCom Merger will close in the third quarter of 1998.

         In May 1998, GTE Corporation and three of its subsidiaries filed suit
in the U.S. District Court for the District of Columbia against WorldCom and MCI
seeking to enjoin the MCI/WorldCom Merger on the grounds that it violates U.S.
antitrust laws. WorldCom believes that the complaint is without merit, although
there can be no assurance as to the ultimate result of the suit.



                                       2
<PAGE>   3

        Termination of the MCI/WorldCom Merger Agreement by MCI or WorldCom
under certain conditions will require MCI to pay WorldCom $750 million as a
termination fee and to reimburse WorldCom the $450 million alternative
transaction fee paid by WorldCom to British Telecommunications plc ("BT").
Further, termination of the MCI/WorldCom Merger Agreement by MCI or WorldCom
under certain conditions, would require WorldCom to pay MCI $1.635 billion as a
termination fee.

         Pursuant to an agreement (the "BT Agreement") among MCI, WorldCom and
BT, the prior merger agreement between BT and MCI (the "BT/MCI Merger
Agreement") was terminated, and WorldCom agreed to pay BT an alternative
transaction fee of $450 million and expenses of $15 million payable to BT in
accordance with the BT/MCI Merger Agreement. These fees were paid on November
12, 1997. WorldCom also agreed to pay to BT an additional payment of $250
million in the event that WorldCom is required to make the $1.635 billion
payment to MCI in accordance with the MCI/WorldCom Merger Agreement.

         The foregoing description of the MCI/WorldCom Merger Agreement and the
BT Agreement and the transactions contemplated thereby does not purport to be
complete and is qualified in its entirety by reference to such agreements,
copies of which are incorporated by reference as exhibits to the WorldCom Annual
Report on Form 10-K for the year ended December 31, 1997, which is incorporated
by reference herein.  Additional information regarding such agreements and the
transactions contemplated thereby (as of January 22, 1998) is also contained in
portions of WorldCom's Proxy Statement/Prospectus dated January 22, 1998 under
the captions "The MCI/WorldCom Merger - Interests of Certain Persons in the
Transaction," "Other Terms of the MCI/WorldCom Merger Agreement," "The BT
Agreement" and "Certain Regulatory Filings and Approvals" included in WorldCom's
Registration Statement on Form S-4, as amended (No. 333-36901), which portions
are hereby incorporated by reference herein.

(2) On July 15, 1998, MCI announced that it had entered into a letter agreement
(the "Letter Agreement") with Cable and Wireless plc ("Cable & Wireless") to
sell its Internet backbone facilities and wholesale and retail Internet business
(the "iMCI Business") for $1.75 billion in cash.  The sale of the iMCI Business
includes all associated traffic, revenue and backbone facilities.  Cable &
Wireless will acquire the following Internet assets:  MCI's U.S. nationwide
Internet backbone, MCI's dedicated access customers, MCI's Internet service
provider customers, MCI's dial-up business and MCI's web hosting and managed
firewall services.  In connection with the transaction, MCI has agreed to
provide Cable & Wireless underlying transport service for Cable & Wireless's
Internet backbone for up to five years.  MCI and Cable & Wireless have also
agreed to non-competition agreements for transitioning accounts of 24 and 18
months for wholesale and dedicated access retail customers, respectively. In
addition, approximately 1,000 MCI employees - in engineering, sales, customer
service, marketing, operations and administrative support - may be transferred
to Cable & Wireless.  The sale of the iMCI Business to Cable & Wireless is
contingent upon receipt of U.S. Department of Justice and European Commission
approval of the sale and the final regulatory approval of the MCI/WorldCom
Merger.  The Letter Agreement will terminate if such governmental approvals are
not received by December 31, 1998.

         MCI's agreement with Cable & Wireless has no immediate impact on MCI's
Internet customers.  They will continue to receive Internet service from MCI
until the close of the MCI/WorldCom Merger when the agreement with Cable &
Wireless becomes effective.  At that time, they will become Cable & Wireless
Internet customers.  Subject to the terms of the Letter Agreement, MCI/WorldCom
will offer a full suite of Internet services upon completion of the MCI/WorldCom
Merger.

(3)  WorldCom currently is in the process of arranging a $12.0 billion bank
credit facility (the "New Credit Facility"), consisting of the amendment and
restatement of its existing $5.0 billion facility and the arrangement of a new
$7.0 billion 364-day revolving credit facility. The $5.0 billion facility will
consist of a $3.75 billion Facility A Revolving Credit Agreement ("Facility A")
and a $1.25 billion Facility B Term Loan Agreement ("Facility B"). Facility A
and Facility B will mature on June 30, 2002, and the $7.0 billion revolving
credit facility ("Facility C") will mature 364 days from the closing of the
Facilities, with options to extend Facility C for two additional 364-day periods
(subject to 51% approval by the lenders) and to convert up to $4.0 billion of
outstanding borrowings thereunder into a one-year term loan. The Company expects
the New Credit Facility to contain pricing, covenants and events of default that
are generally no less favorable than those contained in its existing credit
facilities. The New Credit Facility is expected to be finalized in early August
1998. As of this date, WorldCom has secured commitments, subject to satisfactory
documentation and certain other conditions, in excess of the aggregate amount of
the New Credit Facility. There can be no assurance that the New Credit Facility
will be completed or that committed amounts will be made available to the
Company.

(4)  On July 30, 1998, MCI issued its second quarter 1998 earnings release,
certain portions of which are attached hereto as Exhibit 99.1 and are
incorporated herein by reference. Information regarding WorldCom's results for
the three months ended June 30, 1998 is contained in WorldCom's Current Report
on Form 8-K dated July 23, 1998 (filed July 24, 1998).

ITEM 7.  Financial Statements, Pro Forma Financial Information and Exhibits.

         The following exhibits are filed herewith in accordance with Item 601
of Regulation S-K:



                                       3
<PAGE>   4

            (c)   Exhibit Index

  Exhibit No.                        Description
  -----------                        -----------

  99.1              Certain portions of MCI's Press release dated July 30, 1998.

  99.2              Portions of WorldCom's Proxy Statement/Prospectus dated  
                    January 22, 1998 under the captions "The MCI/WorldCom Merger
                    - Interests of Certain Persons in the Transaction," "Other
                    Terms of the MCI/WorldCom Merger Agreement," "The BT
                    Agreement" and "Certain Regulatory Filings and Approvals"
                    contained in WorldCom's Registration Statement on Form S-4,
                    as amended (No. 333-36901), which portions are hereby
                    incorporated by reference herein. 


                                       4

<PAGE>   5

                                   SIGNATURES

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


                                                  WORLDCOM, INC.



                                               By: /s/ SCOTT D. SULLIVAN
                                                  -----------------------------
                                                  Scott D. Sullivan
                                                  Chief Financial Officer

August 4, 1998


                                       5

<PAGE>   6



                                 EXHIBIT INDEX


<TABLE>
<CAPTION>

      Exhibit No.                 Description of Exhibit
      -----------                 ----------------------
<S>                 <C>
      99.1          Certain portions of MCI's press release dated July 30, 1998.

      99.2          Portions of WorldCom's Proxy Statement/Prospectus dated
                    January 22, 1998 under the captions "The MCI/WorldCom
                    Merger - Interests of Certain Persons in the Transaction,"
                    "Other Terms of the MCI/WorldCom Merger Agreement," "The BT
                    Agreement" and "Certain Regulatory Filings and Approvals"
                    contained in WorldCom's Registration Statement on Form S-4,
                    as amended (No. 333-36901), which portions are hereby
                    incorporated by reference herein. 
</TABLE>