
<PAGE>
 
As filed with the Securities and Exchange Commission on December 6, 1996.

                      SECURITIES AND EXCHANGE COMMISSION

                            Washington, D.C. 20549


                                  FORM 8-A/A

                      FOR REGISTRATION OF CERTAIN CLASSES
                OF SECURITIES PURSUANT TO SECTION 12(b) OR (g)
                    OF THE SECURITIES EXCHANGE ACT OF 1934

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

                                 CompUSA Inc.
            (Exact name of registrant as specified in its charter)


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


        Delaware                                                 75-2261497
(State of incorporation or organization)                       (IRS Employer
                                                            Identification No.)
 
                          14951 North Dallas Parkway
                              Dallas, Texas 75240
                   (Address of principal executive offices,
                              including zip code)

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

       SECURITIES TO BE REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:
 
 ===============================================================================
      Title of each class                       Name of each exchange on which
      to be so registered                       each class is to be registered
 -------------------------------------------------------------------------------
 
  Common Stock, $.01 par value                     New York Stock Exchange

================================================================================

       SECURITIES TO BE REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT:
 
                                Not applicable

================================================================================
<PAGE>
 
Item 1.  Description of the Registrant's Securities to be Registered.
         ----------------------------------------------------------- 

     This Registration Statement relates to the registration of the Common
Stock, par value $0.01 per share ("Common Stock"), of CompUSA Inc., a Delaware
corporation (the "Company"), pursuant to Section 12(b) of the Securities
Exchange Act of 1934, as amended (the "Act").  The  following is a description
of the Company's capital stock.

     The authorized capital stock of the Company consists of 200,000,000 shares
of Common Stock and 10,000 shares of preferred stock, par value $.01 per share
("Preferred Stock"), 2,500 shares of which have been designated Series A Junior
Participating Preferred Stock.  See "Rights Plan."

COMMON STOCK

     The Common Stock is listed on the NYSE under the symbol "CPU." At December
3, 1996, there were 90,972,440 shares of Common Stock outstanding, held by
approximately 1,398 holders of record.

     Holders of shares of Common Stock are entitled to one vote per share on
matters to be voted upon by the stockholders, and, subject to the prior rights
of the holders of Preferred Stock, to receive dividends when and as declared by
the Board of Directors with funds legally available therefor and to share
ratably in the assets of the Company legally available for distribution to the
stockholders in the event of liquidation or dissolution, after payment of all
debts and other liabilities.  Holders of the Common Stock are not entitled to
preemptive rights and have no subscription, redemption or conversion privileges.
The Common Stock does not have cumulative voting rights, which means the holder
or holders of more than one-half of the shares voting for the election of
directors can elect all the directors then being elected.  All the outstanding
shares of Common Stock are fully paid and nonassessable.  The rights,
preferences and privileges of holders of Common Stock are subject to the rights
of the holders of shares of any series of Preferred Stock the Company may issue
in the future.

PREFERRED STOCK

     At December 3, 1996, there were no shares of Preferred Stock outstanding.
The Company has no present plans to issue any shares of Preferred Stock, except
as set forth under "Rights Plan" below.  However, the Board of Directors has the
authority, without further stockholder approval, to issue shares of Preferred
Stock in one or more series and to determine the dividend rights, any conversion
rights or rights of exchange, voting rights, rights and terms of redemption
(including sinking fund provisions), liquidation preferences and any other
rights, preferences, privileges and restrictions of any series of Preferred
Stock, and the number of shares constituting such series and the designation
thereof.  The indenture related to the Company's 9 1/2% Senior Subordinated
Notes due 2000 (the "Senior Subordinated Notes") limits the Company's ability to
issue Preferred Stock.

                                       2
<PAGE>
 
     The issuance of Preferred Stock may have the effect of delaying, deterring
or preventing a change in control of the Company, making removal of the present
management of the Company more difficult or resulting in restrictions upon the
payment of dividends and other distributions to the holders of Common Stock.

RIGHTS PLAN

     On April 29, 1994, the Board of Directors of the Company declared a
dividend of one right to purchase preferred stock (a "Right") for each
outstanding share of Common Stock to stockholders of record at the close of
business on May 9, 1994.  Each share of subsequently issued Common Stock will
also incorporate one Right.  The Rights will expire on April 28, 2004.  Each
Right will entitle stockholders, in certain circumstances, to buy one ten-
thousandth of a newly issued share of Series A Junior Participating Preferred
Stock (the "Junior Preferred Stock") of the Company at an initial purchase price
of $120.

     The Rights will be exercisable and transferable apart from the Common Stock
only if a person or group acquires beneficial ownership of 20% or more of the
Common Stock, or commences a tender or exchange offer upon consummation of which
such person or group would beneficially own 20% or more of the Common Stock.

     The Company will generally be entitled to redeem the Rights at $.001 per
Right at any time until a person or group has become the beneficial owner of 20%
or more of the Common Stock.  Under the Rights "flip-in" feature, if any person
or group becomes the beneficial owner of 20% or more of the Common Stock, then
each Right not owned by such person or group of certain related parties will
entitle its holder to purchase, at the Right's then current purchase price,
shares of Common Stock (or in certain circumstances as determined by the Board
of Directors, cash, other property or other securities) having a value of twice
the Right's purchase price.

     Under the Rights "flip-over" provision, if, after any person or group
becomes the beneficial owner of 20% or more of the Common Stock, the Company is
involved in a merger or other business combination transaction with another
person, or sells 50% or more of its assets or earning power in one or more
transactions, each Right will entitle its holder to purchase, at the Right's
then current purchase price, shares of common stock of such other person having
a value of twice the Right's purchase price.

     The Junior Preferred Stock will not be redeemable and, unless otherwise
provided in connection with the creation of a subsequent series of Preferred
Stock, will be subordinate to all other series of Preferred Stock.  Each share
of Junior Preferred Stock will represent the right to receive, when and if
declared, a quarterly dividend at an annual rate equal to the greater of $1.00
per share or 10,000 times the quarterly per share cash dividends declared on the
Common Stock during the immediately preceding fiscal year.  In addition, each
share of Junior Preferred Stock will represent the right to receive 10,000 times
any noncash dividends (other than dividends payable in Common Stock) declared on
the Common Stock, in like kind.  In the event of the liquidation,

                                       3
<PAGE>
 
dissolution or winding up of the Company, each share of Junior Preferred Stock
will represent the right to receive a liquidation payment in an amount equal to
the greater of $1.00 per share or 10,000 times the liquidation payment made per
share of Common Stock.  Each share of Junior Preferred Stock will have 10,000
votes, voting together with the Common Stock.  In the event of any merger,
consolidation or other transaction in which common shares are exchanged, each
share of Junior Preferred Stock represents the right to receive 10,000 times the
amount received per share of Common Stock.  The rights of the Junior Preferred
Stock as to dividends, liquidation, voting rights and merger participation are
protected by anti-dilution provisions.

OTHER CHARTER AND BYLAW PROVISIONS

     The Company's Restated and Amended Certificate of Incorporation (the
"Charter") and the Company's Restated and Amended Bylaws (the "Bylaws") contain
provisions prohibiting stockholder action by written consent by less than all
the stockholders; limiting the right to call stockholder meetings to the
Chairman of the Board, the President or the Board of Directors; requiring
advance notice for submission of stockholder proposals or nominees to be voted
on at stockholder meetings; prohibiting the stockholders from removing directors
from office except for cause and reserving to the directors the exclusive right
to change the number of directors or to fill vacancies on the Board; and
requiring a vote of stockholders owning 66 1/3% of the outstanding shares to
amend certain provisions of the Charter and Bylaws. The Charter also provides
for the Board of Directors to be divided into three classes of directors serving
staggered three-year terms. As a result, approximately one-third of the Board of
Directors will be elected each year.

TRANSFER AGENT AND REGISTRAR

     American Stock Transfer & Trust Company, New York, New York, is the
transfer agent and registrar for the Common Stock.

Item 2.  Exhibits.
         -------- 

     The Common Stock is listed on the New York Stock Exchange, on which other
securities of the Company are listed.  In accordance with Part I of the
Instructions to Exhibits on Form 8-A, the following exhibits are being filed
with each copy of this Registration Statement, or are incorporated by reference
herein:

                                       4
<PAGE>
 
                                   EXHIBITS
 
                       Description                          Exhibit
                       -----------                          -------

Restated and Amended Certificate of Incorporation of the       3
 Company.(1)

Restated and Amended Bylaws of the Company.(2)                 --
 
____________
(1)  Filed herewith.
(2)  Previously filed as an exhibit to the Company's Quarterly Report on Form
     10-Q for the quarter ended March 26, 1994 and incorporated herein by
     reference.

                                       5
<PAGE>
 
                                   SIGNATURE


     Pursuant to the requirements of Section 12 of the Securities Exchange Act
of 1934, the registrant has duly caused this Registration Statement to be signed
on its behalf by the undersigned, thereto duly authorized.

                                    CompUSA Inc.



Date:   December 5, 1996            By /s/ Mark R. Walker
                                      -----------------------------------------
                                    Mark R. Walker,
                                    Senior Vice President-General Counsel

                                       6
