<PAGE>   1
        AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 29, 1996

                                                     REGISTRATION NO. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


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


                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933


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


                          RATIONAL SOFTWARE CORPORATION
                          (FORMERLY VERDIX CORPORATION)
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)


       DELAWARE                                         54-1217099
(STATE OF INCORPORATION)                (I.R.S. EMPLOYER (IDENTIFICATION NUMBER)


                            2800 SAN TOMAS EXPRESSWAY
                          SANTA CLARA, CALIFORNIA 95051
                    (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)

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

              RATIONAL SOFTWARE CORPORATION 1994 STOCK OPTION PLAN

                            (FULL TITLE OF THE PLAN)

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

                                 ROBERT T. BOND
                 SENIOR VICE PRESIDENT, CHIEF OPERATING OFFICER,
                      CHIEF FINANCIAL OFFICER AND SECRETARY
                          RATIONAL SOFTWARE CORPORATION
                            2800 SAN TOMAS EXPRESSWAY
                          SANTA CLARA, CALIFORNIA 95051
                     (NAME AND ADDRESS OF AGENT FOR SERVICE)


                                 (408) 496-3600
          (TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE)


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

                                   Copies to:

                              CRAIG H. FACTOR, ESQ.
                       WILSON, SONSINI, GOODRICH & ROSATI
                               650 PAGE MILL ROAD
                        PALO ALTO, CALIFORNIA 94304-1050


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




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

                                      
                                                           

<PAGE>   2
                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
===================================================================================================================
                                                   PROPOSED                PROPOSED
                                                    MAXIMUM                MAXIMUM
  TITLE OF SECURITIES      AMOUNT TO BE       OFFERING PRICE PER      AGGREGATE OFFERING        AMOUNT OF
   TO BE REGISTERED         REGISTERED             SHARE(1)                PRICE(1)          REGISTRATION FEE
===================================================================================================================
<S>                          <C>                  <C>                     <C>                  <C>
Common Stock,
$0.01 par value:             2,000,000              $38.50                $77.000.000          $23,333.33
                             ---------            ----------              -----------          -----------

===================================================================================================================
</TABLE>


(1)      The proposed maximum offering price per share was estimated pursuant to
         Rule 457(c) and 457(h) under the Securities Act. The Proposed Maximum
         Offering Price Per Share was determined by reference to 100% of the
         average of the high and the low prices reported in The Nasdaq Stock
         Market on October 22, 1996, which average was $38.50.


<PAGE>   3
         This Registration Statement on Form S-8 is being filed in order to
register 2,000,000 additional shares which have been reserved for the 1994 Stock
Option Plan. In addition, Exhibit 4.6, as previously filed with the Rational
Software Corporation Form S-8 (Registration No. 33-97044), has been replaced
with an updated version of the 1994 Stock Option Plan attached hereto as Exhibit
4.6. The Registration Statements on Form S-8 (Registration No. 33-77382 and
33-97044) are hereby incorporated by reference.

                                INDEX TO EXHIBITS

Exhibit Number
--------------
4.6      Rational Software Corporation 1994 Stock Option Plan.

5.1      Opinion of Wilson, Sonsini, Goodrich & Rosati as to legality of 
         securities being registered.

23.1     Consent of Ernst & Young LLP, Independent Auditors.

23.2     Consent of Counsel (contained in Exhibit 5.1).

24.1     Power of Attorney (contained on page II-1).




                                        


<PAGE>   4
                                   SIGNATURES

         Pursuant to the requirements of Section 13 or 15(d) 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 on Form S-8 and has duly caused
this Registration Statement to be signed on its behalf by the undersigned,
thereunto duly authorized, in the City of Santa Clara, State of California, on
October 29, 1996.

                       RATIONAL SOFTWARE CORPORATION


                       By: /s/ Robert T. Bond
                           -----------------------------------------------
                           Robert T. Bond
                           Senior Vice President, Chief Operating Officer, 
                           Chief Financial Officer and Secretary


                                POWER OF ATTORNEY

         KNOW ALL THESE PERSONS BY THESE PRESENTS, that each person whose
signature appears below constitutes and appoints Paul D. Levy and Robert T. Bond
and each of them, jointly and severally, his attorneys-in-fact, each with full
power of substitution, for him in any and all capacities, to sign any and all
amendments to this Registration Statement on Form S-8 and to file the same, with
exhibits thereto and other documents in connection therewith, with the
Securities and Exchange Commission, hereby ratifying and confirming all that
each said attorneys-in-fact or his substitute or substitutes, may do or cause to
be done by virtue hereof.

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


<TABLE>
<CAPTION>
<S>                                  <C>                                    
Date:   October 29, 1996              /s/ Michael T. Devlin
       ------------------            -----------------------------------
                                     Michael T. Devlin, President and Director

Date:   October 29, 1996              /s/ Paul D. Levy
       -----------------             -----------------------------------
                                     Paul D. Levy, Chairman of the Board and Chief Executive Officer

Date:   October 29, 1996              /s/ Robert T. Bond
       -----------------             -----------------------------------
                                     Robert T. Bond, Senior Vice President
                                     Chief Operating Officer, Chief Financial Officer, and Secretary

Date:   October 29, 1996              /s/ James S. Campbell
       -----------------             -----------------------------------
                                     James S. Campbell, Director

Date:   
       -----------------             -----------------------------------
                                     Daniel H. Case III, Director

Date:   October 29, 1996              /s/ Leslie G. Denend
       -----------------             -----------------------------------
                                     Leslie G. Denend, Director

Date:   October 29, 1996              /s/ John E. Montague
       -----------------             -----------------------------------
                                     John E. Montague, Director

Date:   October 29, 1996              /s/ Allison R. Schleicher
       -----------------             -----------------------------------
                                     Allison R. Schleicher, Director

Date:   October 29, 1996              /s/ Timothy A. Brennan
       -----------------             -----------------------------------
                                     Timothy A. Brennan, Vice President,
                                     Finance and Administration
                                     (Principal Accounting Officer)
</TABLE>

                                      II-1
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 8899}]
{"company-data": {"conformed-name": "RATIONAL SOFTWARE CORP", "cik": "0000722056", "assigned-sic": "7372", "irs-number": "541217099", "state-of-incorporation": "DE", "fiscal-year-end": "0331"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-15015", "film-number": "96649351"}, "business-address": {"street1": "2800 SAN TOMAS EXPRESSWAY", "city": "SANTA CLARA", "state": "CA", "zip": "95051-0951", "phone": "4084963600"}, "mail-address": {"street1": "2800 SAN TOMAS EXPRESSWAY", "city": "SANTA CLARA", "state": "CA", "zip": "95051-0951"}, "former-company": {"former-conformed-name": "VERDIX CORP", "date-changed": "19920703"}}
1
        AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 29, 1996

                                                     REGISTRATION NO. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

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

                          RATIONAL SOFTWARE CORPORATION
                          (FORMERLY VERDIX CORPORATION)
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

       DELAWARE                                         54-1217099
(STATE OF INCORPORATION)                (I.R.S. EMPLOYER (IDENTIFICATION NUMBER)

                            2800 SAN TOMAS EXPRESSWAY
                          SANTA CLARA, CALIFORNIA 95051
                    (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)

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

              RATIONAL SOFTWARE CORPORATION 1994 STOCK OPTION PLAN

                            (FULL TITLE OF THE PLAN)

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

                                 ROBERT T. BOND
                 SENIOR VICE PRESIDENT, CHIEF OPERATING OFFICER,
                      CHIEF FINANCIAL OFFICER AND SECRETARY
                          RATIONAL SOFTWARE CORPORATION
                            2800 SAN TOMAS EXPRESSWAY
                          SANTA CLARA, CALIFORNIA 95051
                     (NAME AND ADDRESS OF AGENT FOR SERVICE)

                                 (408) 496-3600
          (TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE)

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

                                   Copies to:

                              CRAIG H. FACTOR, ESQ.
                       WILSON, SONSINI, GOODRICH & ROSATI
                               650 PAGE MILL ROAD
                        PALO ALTO, CALIFORNIA 94304-1050

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

================================================================================
2
                         CALCULATION OF REGISTRATION FEE
===================================================================================================================
                                                   PROPOSED                PROPOSED
                                                    MAXIMUM                MAXIMUM
  TITLE OF SECURITIES      AMOUNT TO BE       OFFERING PRICE PER      AGGREGATE OFFERING        AMOUNT OF
   TO BE REGISTERED         REGISTERED             SHARE(1)                PRICE(1)          REGISTRATION FEE
===================================================================================================================
Common Stock,
$0.01 par value:             2,000,000              $38.50                $77.000.000          $23,333.33
                             ---------            ----------              -----------          -----------

===================================================================================================================
(1)      The proposed maximum offering price per share was estimated pursuant to
         Rule 457(c) and 457(h) under the Securities Act. The Proposed Maximum
         Offering Price Per Share was determined by reference to 100% of the
         average of the high and the low prices reported in The Nasdaq Stock
         Market on October 22, 1996, which average was $38.50.
3
         This Registration Statement on Form S-8 is being filed in order to
register 2,000,000 additional shares which have been reserved for the 1994 Stock
Option Plan. In addition, Exhibit 4.6, as previously filed with the Rational
Software Corporation Form S-8 (Registration No. 33-97044), has been replaced
with an updated version of the 1994 Stock Option Plan attached hereto as Exhibit
4.6. The Registration Statements on Form S-8 (Registration No. 33-77382 and
33-97044) are hereby incorporated by reference.

                                INDEX TO EXHIBITS

Exhibit Number
--------------
4.6      Rational Software Corporation 1994 Stock Option Plan.

5.1      Opinion of Wilson, Sonsini, Goodrich & Rosati as to legality of 
         securities being registered.

23.1     Consent of Ernst & Young LLP, Independent Auditors.

23.2     Consent of Counsel (contained in Exhibit 5.1).

24.1     Power of Attorney (contained on page II-1).
4
                                   SIGNATURES

         Pursuant to the requirements of Section 13 or 15(d) 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 on Form S-8 and has duly caused
this Registration Statement to be signed on its behalf by the undersigned,
thereunto duly authorized, in the City of Santa Clara, State of California, on
October 29, 1996.

                       RATIONAL SOFTWARE CORPORATION

                       By: /s/ Robert T. Bond
                           -----------------------------------------------
                           Robert T. Bond
                           Senior Vice President, Chief Operating Officer, 
                           Chief Financial Officer and Secretary

                                POWER OF ATTORNEY

         KNOW ALL THESE PERSONS BY THESE PRESENTS, that each person whose
signature appears below constitutes and appoints Paul D. Levy and Robert T. Bond
and each of them, jointly and severally, his attorneys-in-fact, each with full
power of substitution, for him in any and all capacities, to sign any and all
amendments to this Registration Statement on Form S-8 and to file the same, with
exhibits thereto and other documents in connection therewith, with the
Securities and Exchange Commission, hereby ratifying and confirming all that
each said attorneys-in-fact or his substitute or substitutes, may do or cause to
be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated:
Date:   October 29, 1996              /s/ Michael T. Devlin
       ------------------            -----------------------------------
                                     Michael T. Devlin, President and Director

Date:   October 29, 1996              /s/ Paul D. Levy
       -----------------             -----------------------------------
                                     Paul D. Levy, Chairman of the Board and Chief Executive Officer

Date:   October 29, 1996              /s/ Robert T. Bond
       -----------------             -----------------------------------
                                     Robert T. Bond, Senior Vice President
                                     Chief Operating Officer, Chief Financial Officer, and Secretary

Date:   October 29, 1996              /s/ James S. Campbell
       -----------------             -----------------------------------
                                     James S. Campbell, Director

Date:   
       -----------------             -----------------------------------
                                     Daniel H. Case III, Director

Date:   October 29, 1996              /s/ Leslie G. Denend
       -----------------             -----------------------------------
                                     Leslie G. Denend, Director

Date:   October 29, 1996              /s/ John E. Montague
       -----------------             -----------------------------------
                                     John E. Montague, Director

Date:   October 29, 1996              /s/ Allison R. Schleicher
       -----------------             -----------------------------------
                                     Allison R. Schleicher, Director

Date:   October 29, 1996              /s/ Timothy A. Brennan
       -----------------             -----------------------------------
                                     Timothy A. Brennan, Vice President,
                                     Finance and Administration
                                     (Principal Accounting Officer)
II-1