<PAGE>   1


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

                                 FORM 10-K/A-1

                [X] ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
                   FOR THE FISCAL YEAR ENDED DECEMBER 31, 1998
                                       OR

            [ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
                 FOR THE TRANSITION PERIOD FROM        TO

                         COMMISSION FILE NUMBER 1-14328

                        TRAVELERS PROPERTY CASUALTY CORP.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

          DELAWARE                                              06-1445591
(STATE OR OTHER JURISDICTION                                 (I.R.S. EMPLOYER
OF INCORPORATION OR ORGANIZATION)                          IDENTIFICATION NO.)

                  ONE TOWER SQUARE, HARTFORD, CONNECTICUT 06183
               (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES) (ZIP CODE)
                                 (860) 277-0111
              (REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE)

SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:

<TABLE>
<CAPTION>
<S>                                                                              <C>
                                TITLE OF EACH CLASS                              NAME OF EACH EXCHANGE ON WHICH REGISTERED
                                -------------------                              -----------------------------------------
                  CLASS A COMMON STOCK, PAR VALUE $ .01 PER SHARE                         NEW YORK STOCK EXCHANGE
                          6-3/4% NOTES DUE APRIL 15, 2001                                 NEW YORK STOCK EXCHANGE
             8.08% TRUST PREFERRED SECURITIES OF SUBSIDIARY TRUST (AND                    NEW YORK STOCK EXCHANGE
                    REGISTRANT'S GUARANTY WITH RESPECT THERETO)
               8% TRUST PREFERRED SECURITIES OF SUBSIDIARY TRUST (AND                     NEW YORK STOCK EXCHANGE
                    REGISTRANT'S GUARANTY WITH RESPECT THERETO)
</TABLE>

SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT:  NONE

INDICATE BY CHECK MARK WHETHER THE REGISTRANT (1) HAS FILED ALL REPORTS REQUIRED
TO BE FILED BY SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 DURING
THE PRECEDING 12 MONTHS (OR FOR SUCH SHORTER PERIOD THAT THE REGISTRANT WAS
REQUIRED TO FILE SUCH REPORTS), AND (2) HAS BEEN SUBJECT TO SUCH FILING
REQUIREMENTS FOR THE PAST 90 DAYS. YES X   NO

INDICATE BY CHECK MARK IF DISCLOSURE OF DELINQUENT FILERS PURSUANT TO ITEM 405
OF REGULATION S-K IS NOT CONTAINED HEREIN, AND WILL NOT BE CONTAINED, TO THE
BEST OF REGISTRANT'S KNOWLEDGE, IN DEFINITIVE PROXY OR INFORMATION STATEMENTS
INCORPORATED BY REFERENCE IN PART III OF THIS FORM 10-K OR ANY AMENDMENT TO THIS
FORM 10-K. [X]

THE AGGREGATE MARKET VALUE OF THE VOTING STOCK HELD BY NONAFFILIATES OF THE
REGISTRANT AS OF MARCH 3, 1999 WAS APPROXIMATELY $2.28 BILLION.

AS OF MARCH 3, 1999, 63,388,266 SHARES OF THE REGISTRANT'S CLASS A COMMON STOCK,
PAR VALUE $ .01 PER SHARE, AND 328,020,170 SHARES OF THE REGISTRANT'S CLASS B
COMMON STOCK, PAR VALUE $.01 PER SHARE, WERE OUTSTANDING.

                       DOCUMENTS INCORPORATED BY REFERENCE

CERTAIN PORTIONS OF THE REGISTRANT'S ANNUAL REPORT TO STOCKHOLDERS FOR THE
FISCAL YEAR ENDED DECEMBER 31, 1998 ARE INCORPORATED BY REFERENCE INTO PART II
OF THIS FORM 10-K.

CERTAIN PORTIONS OF THE REGISTRANT'S PROXY STATEMENT FOR THE 1999 ANNUAL MEETING
OF STOCKHOLDERS TO BE HELD ON APRIL 20, 1999 ARE INCORPORATED BY REFERENCE INTO
PART III OF THIS FORM 10-K.
<PAGE>   2
                               EXPLANATORY NOTE


      This Form 10-K/A-1 is being filed to include as an exhibit to the
Form 10-K financial statements for the Travelers Group Inc. 401(k) Savings Plan
pursuant to Rule 15d-21 of the Securities Exchange Act of 1934, as amended.
Other than the related additions to the Exhibit Index, the text of Item 14 has
not been amended and speaks as of the date of the original filing of the
Form 10-K.






































                                      2
<PAGE>   3
                                    PART IV

ITEM 14.      EXHIBITS, FINANCIAL STATEMENT SCHEDULES, AND
              REPORTS ON FORM 8-K.

(a)      Documents filed as a part of the report:

         (1)      Financial Statements. See Index to Consolidated Financial
                  Statements and Schedules on page F-1 hereof.

         (2)      Financial Statement Schedules. See Index to Consolidated
                  Financial Statements and Schedules on page F-1 hereof.

         (3)      Exhibits:

                  See Exhibit Index.

(b)      Reports on Form 8-K:


                  No reports on Form 8-K were filed during the fourth
                  quarter of 1998.


                                       3


<PAGE>   4
'                                 EXHIBIT INDEX



         EXHIBIT
         NUMBER   DESCRIPTION OF EXHIBIT
         ------   ----------------------

         3.01     Restated Certificate of Incorporation of Travelers Property
                  Casualty Corp. (the "Company"), Certificate of Designations,
                  Powers, Preferences and Rights of 7.5% Redeemable Preferred
                  Stock, Series Z, of the Company, Certificate of Amendment to
                  the Restated Certificate of Incorporation, filed March 7,
                  1997, and Certificate of Amendment to the Restated Certificate
                  of Incorporation, filed April 23, 1997, incorporated by
                  reference to Exhibit 3.01 to the Company's Quarterly Report on
                  Form 10-Q for the fiscal quarter ended March 31, 1997 (File
                  No.1-14328) (the "Company's 3/31/97 10-Q").

         3.02     Restated By-Laws of the Company, effective April 23, 1997,
                  incorporated by reference to Exhibit 3.02 to the Company's
                  3/31/97 10-Q.

         4.01     Intercompany Agreement, dated as of April 2, 1996, between
                  Travelers Group Inc. and the Company, incorporated by
                  reference to Exhibit 4.1 to the Company's Form S-1.

         4.02.1   Shareholders Agreement, dated as of April 2, 1996, by and
                  among the Company, The Travelers Insurance Group Inc., Aetna
                  Life and Casualty Company (now known as Aetna Services, Inc.),
                  J.P. Morgan Capital Corporation, The Trident Partnership L.P.
                  and Fund American Enterprises Holdings, Inc., incorporated by
                  reference to Exhibit 4.2 to the Company's Form S-1.

         4.02.2   Amendment to Shareholders Agreement, dated June 20, 1997, by
                  and among the Company, Aetna Services, Inc., J.P. Morgan
                  Capital Corporation, The Trident Partnership L.P. and Fund
                  American Enterprises Holdings, Inc., incorporated by reference
                  to the Company's Annual Report on Form 10-K for the fiscal
                  year ended December 31, 1997 (File No. 1-14328) (the
                  "Company's 1997 10-K").


                                       4


<PAGE>   5
         EXHIBIT
         NUMBER   DESCRIPTION OF EXHIBIT
         ------   ----------------------

         10.01*   Travelers Property Casualty Corp. Capital Accumulation Plan
                  (as amended through July 23, 1997), incorporated by reference
                  to Exhibit 10.01 to the Company's Quarterly Report on Form
                  10-Q for the fiscal quarter ended September 30, 1997 (File No.
                  1-14328).

         10.02*   Travelers Property Casualty Corp. 1996 Executive Option Plan
                  (as amended through March 7, 1997), incorporated by reference
                  to Exhibit 10.03 to the Company's Annual Report on Form 10-K
                  for the fiscal year ended December 31, 1996 (File No.1-14328)
                  (the "Company's 1996 10-K").

         10.03*   Travelers Property Casualty Corp. Executive Performance
                  Compensation Plan (as amended through March 7, 1997),
                  incorporated by reference to Exhibit 10.04 to the Company's
                  1996 10-K.

         10.04*   Travelers Property Casualty Corp. 1996 Deferred Compensation
                  Plan for Non-Employee Directors (as amended through September
                  25, 1996), incorporated by reference to Exhibit 10.02 to the
                  Company's Quarterly Report on Form 10-Q for the fiscal quarter
                  ended September 30, 1996 (File No.1-14328).

         10.05*   Travelers Group Capital Accumulation Plan (as amended through
                  July 23, 1997), incorporated by reference to Exhibit 10.02 to
                  the Quarterly Report on Form 10-Q of Travelers Group Inc. for
                  the fiscal quarter ended September 30, 1997 (File No. 1-9924)
                  (the "TRV 9/30/97 10-Q").

         10.06.1* Travelers Group Stock Option Plan (as amended and restated as
                  of April 24, 1996), incorporated by reference to Exhibit
                  10.02.1 to the Annual Report on Form 10-K of Travelers Group
                  Inc. for the fiscal year ended December 31, 1996 (File No.
                  1-9924) (the "TRV 1996 10-K").

         10.06.2* Amendment No. 14 to the Travelers Group Stock Option Plan,
                  incorporated by reference to Exhibit 10.01 to the Quarterly
                  Report on Form 10-Q of Travelers Group Inc. for the fiscal
                  quarter ended September 30, 1996 (File No. 1-9924).

         10.06.3* Amendment No. 15 to the Travelers Group Stock Option Plan,
                  incorporated by reference to Exhibit 10.04 to the TRV 9/30/97
                  10-Q.

                                       5


<PAGE>   6
         EXHIBIT
         NUMBER   DESCRIPTION OF EXHIBIT
         ------   ----------------------

         10.07*   Travelers Group 1996 Stock Incentive Plan (as amended through
                  July 23, 1997), incorporated by reference to Exhibit 10.03 to
                  the TRV 9/30/97 10-Q.

         10.08*   Travelers Group Inc. Retirement Benefit Equalization Plan of
                  Travelers Group Inc. (as amended and restated as of January 2,
                  1996), incorporated by reference to Exhibit 10.04 to Citigroup
                  Inc.'s Annual Report on Form 10-K for the fiscal year ended
                  December 31, 1998 (File No. 1-9934) (the "Citigroup 1998
                  10-K").

         10.09    TAPC Tax Allocation Agreement, effective as of January 1, 1996
                  between Travelers Group Inc. and the Company, incorporated by
                  reference to Exhibit 10.9 to the Company's Form S-1.

         10.10    Lease for office space at CityPlace, dated March 28, 1996, by
                  and between Aetna Life and Casualty Company and The Travelers
                  Indemnity Company, incorporated by reference to Exhibit 10.10
                  to the Company's Form S-1.

         10.11    Lease for office space in Hartford, Connecticut, dated as of
                  April 2, 1996, by and between The Travelers Insurance Company
                  and The Travelers Indemnity Company, incorporated by reference
                  to Exhibit 10.14 to the Company's 1996 10-K.

         10.12*   Letter Agreement, dated November 17, 1996, between the Company
                  and Stanton F. Long, incorporated by reference to Exhibit
                  10.15 to the Company's 1996 10-K.

         10.13*   The Travelers Insurance Deferred Compensation Plan (formerly
                  The Travelers Corporation TESIP Restoration and Non-Qualified
                  Savings Plan) (as amended December 10, 1998), incorporated by
                  reference to Exhibit 10.10 to the Citigroup 1998 10-K.



                                       6


<PAGE>   7
         EXHIBIT
         NUMBER   DESCRIPTION OF EXHIBIT
         ------   ----------------------

         11.01    Computation of Earnings Per Share.

         12.01    Computation of Ratio of Earnings to Fixed Charges.

         13.01    Pages 17 through 59 of the 1998 Annual Report to Stockholders
                  of the Company (pagination of exhibit does not correspond to
                  pagination in the 1998 Annual Report to Stockholders).

         21.01    Subsidiaries of the Registrant.

         23.01    Consent of KPMG Peat Marwick LLP, Independent Certified Public
                  Accountants.

         23.02+   Accountants' consent to incorporation by reference of report
                  filed with Exhibit 99.01.

         24.01    Powers of Attorney.

         27.01    Financial Data Schedule.

         99.01+   1998 Financial Statements of Travelers Group Inc. 401(k)
                  Savings Plan, incorporated by reference to Exhibit 99.03 to
                  the Annual Report on Form 10-K/A-1 of Travelers Group Inc.
                  for the fiscal year ended December 31, 1998 (File No. 1-9924).

         The total amount of securities authorized pursuant to any instrument
         defining rights of holders of long-term debt of the Company does not
         exceed 10% of the total assets of the Company and its consolidated
         subsidiaries. The Company will furnish copies of any such instrument to
         the Commission upon request.

         Copies of any of the exhibits referred to above will be furnished at a
         cost of $.25 per page (although no charge will be made for the 1998
         Annual Report on Form 10-K) to security holders who make written
         request therefor to Corporate Communications, Travelers Property
         Casualty Corp., One Tower Square, Hartford, Connecticut 06183.

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

*        Denotes a management contract or compensatory plan or arrangement
         required to be filed as an exhibit pursuant to Item 14(c) of Form 10-K.

+        Filed with Form 10-K/A-1.

Except as otherwise indicated, all exhibits were filed with the initial filing
of the Form 10-K.


                                       7


<PAGE>   8
                                   SIGNATURE

         Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized, on the 29th day of
June, 1999.

                                        TRAVELERS PROPERTY CASUALTY CORP.
                                        (Registrant)

                                        By: /s/ William P. Hannon
                                        ---------------------------------
                                          William P. Hannon
                                          Chief Financial Officer




                                       8

<PAGE>   9
                                  EXHIBIT INDEX



         EXHIBIT
         NUMBER   DESCRIPTION OF EXHIBIT
         ------   ----------------------

         3.01     Restated Certificate of Incorporation of Travelers Property
                  Casualty Corp. (the "Company"), Certificate of Designations,
                  Powers, Preferences and Rights of 7.5% Redeemable Preferred
                  Stock, Series Z, of the Company, Certificate of Amendment to
                  the Restated Certificate of Incorporation, filed March 7,
                  1997, and Certificate of Amendment to the Restated Certificate
                  of Incorporation, filed April 23, 1997, incorporated by
                  reference to Exhibit 3.01 to the Company's Quarterly Report on
                  Form 10-Q for the fiscal quarter ended March 31, 1997 (File
                  No.1-14328) (the "Company's 3/31/97 10-Q").

         3.02     Restated By-Laws of the Company, effective April 23, 1997,
                  incorporated by reference to Exhibit 3.02 to the Company's
                  3/31/97 10-Q.

         4.01     Intercompany Agreement, dated as of April 2, 1996, between
                  Travelers Group Inc. and the Company, incorporated by
                  reference to Exhibit 4.1 to the Company's Form S-1.

         4.02.1   Shareholders Agreement, dated as of April 2, 1996, by and
                  among the Company, The Travelers Insurance Group Inc., Aetna
                  Life and Casualty Company (now known as Aetna Services, Inc.),
                  J.P. Morgan Capital Corporation, The Trident Partnership L.P.
                  and Fund American Enterprises Holdings, Inc., incorporated by
                  reference to Exhibit 4.2 to the Company's Form S-1.

         4.02.2   Amendment to Shareholders Agreement, dated June 20, 1997, by
                  and among the Company, Aetna Services, Inc., J.P. Morgan
                  Capital Corporation, The Trident Partnership L.P. and Fund
                  American Enterprises Holdings, Inc., incorporated by reference
                  to the Company's Annual Report on Form 10-K for the fiscal
                  year ended December 31, 1997 (File No. 1-14328) (the
                  "Company's 1997 10-K").






<PAGE>   10
         EXHIBIT
         NUMBER   DESCRIPTION OF EXHIBIT
         ------   ----------------------

         10.01*   Travelers Property Casualty Corp. Capital Accumulation Plan
                  (as amended through July 23, 1997), incorporated by reference
                  to Exhibit 10.01 to the Company's Quarterly Report on Form
                  10-Q for the fiscal quarter ended September 30, 1997 (File No.
                  1-14328).

         10.02*   Travelers Property Casualty Corp. 1996 Executive Option Plan
                  (as amended through March 7, 1997), incorporated by reference
                  to Exhibit 10.03 to the Company's Annual Report on Form 10-K
                  for the fiscal year ended December 31, 1996 (File No.1-14328)
                  (the "Company's 1996 10-K").

         10.03*   Travelers Property Casualty Corp. Executive Performance
                  Compensation Plan (as amended through March 7, 1997),
                  incorporated by reference to Exhibit 10.04 to the Company's
                  1996 10-K.

         10.04*   Travelers Property Casualty Corp. 1996 Deferred Compensation
                  Plan for Non-Employee Directors (as amended through September
                  25, 1996), incorporated by reference to Exhibit 10.02 to the
                  Company's Quarterly Report on Form 10-Q for the fiscal quarter
                  ended September 30, 1996 (File No.1-14328).

         10.05*   Travelers Group Capital Accumulation Plan (as amended through
                  July 23, 1997), incorporated by reference to Exhibit 10.02 to
                  the Quarterly Report on Form 10-Q of Travelers Group Inc. for
                  the fiscal quarter ended September 30, 1997 (File No. 1-9924)
                  (the "TRV 9/30/97 10-Q").

         10.06.1* Travelers Group Stock Option Plan (as amended and restated as
                  of April 24, 1996), incorporated by reference to Exhibit
                  10.02.1 to the Annual Report on Form 10-K of Travelers Group
                  Inc. for the fiscal year ended December 31, 1996 (File No.
                  1-9924) (the "TRV 1996 10-K").

         10.06.2* Amendment No. 14 to the Travelers Group Stock Option Plan,
                  incorporated by reference to Exhibit 10.01 to the Quarterly
                  Report on Form 10-Q of Travelers Group Inc. for the fiscal
                  quarter ended September 30, 1996 (File No. 1-9924).

         10.06.3* Amendment No. 15 to the Travelers Group Stock Option Plan,
                  incorporated by reference to Exhibit 10.04 to the TRV 9/30/97
                  10-Q.




<PAGE>   11
         EXHIBIT
         NUMBER   DESCRIPTION OF EXHIBIT
         ------   ----------------------

         10.07*   Travelers Group 1996 Stock Incentive Plan (as amended through
                  July 23, 1997), incorporated by reference to Exhibit 10.03 to
                  the TRV 9/30/97 10-Q.

         10.08*   Travelers Group Inc. Retirement Benefit Equalization Plan of
                  Travelers Group Inc. (as amended and restated as of January 2,
                  1996), incorporated by reference to Exhibit to 10.04 Citigroup
                  Inc's Annual Report on Form 10-K for the fiscal year ended
                  December 31, 1998 (File No.1-9934) (the ''Citigroup 1998
                  10-K'').


         10.9     TAPC Tax Allocation Agreement, effective as of January 1, 1996
                  between Travelers Group Inc. and the Company, incorporated by
                  reference to Exhibit 10.9 to the Company's Form S-1.

         10.10    Lease for office space at CityPlace, dated March 28, 1996, by
                  and between Aetna Life and Casualty Company and The Travelers
                  Indemnity Company, incorporated by reference to Exhibit 10.10
                  to the Company's Form S-1.

         10.11    Lease for office space in Hartford, Connecticut, dated as of
                  April 2, 1996, by and between The Travelers Insurance Company
                  and The Travelers Indemnity Company, incorporated by reference
                  to Exhibit 10.14 to the Company's 1996 10-K.

         10.12*   Letter Agreement, dated November 17, 1996, between the Company
                  and Stanton F. Long, incorporated by reference to Exhibit
                  10.15 to the Company's 1996 10-K.

         10.13*   The Travelers Insurance Deferred Compensation Plan (formerly
                  The Travelers Corporation TESIP Restoration and Non-Qualified
                  Savings Plan) (as amended December 10,1998), incorporated by
                  reference to Exhibit 10.10 to the Citigroup 1998 10-K.






<PAGE>   12
         EXHIBIT
         NUMBER   DESCRIPTION OF EXHIBIT
         ------   ----------------------

         11.01    Computation of Earnings Per Share.

         12.01    Computation of Ratio of Earnings to Fixed Charges.

         13.01    Pages 17 through 59 of the 1998 Annual Report to Stockholders
                  of the Company (pagination of exhibit does not correspond to
                  pagination in the 1998 Annual Report to Stockholders).

         21.01    Subsidiaries of the Registrant.

         23.01    Consent of KPMG Peat Marwick LLP, Independent Certified Public
                  Accountants.

         23.02+   Accountants' consent to incorporation by reference of report
                  filed with Exhibit 99.01.

         24.01    Powers of Attorney.

         27.01    Financial Data Schedule.

         99.01+   1998 Financial Statements of Travelers Group Inc. 401(k)
                  Savings Plan, incorporated by reference to Exhibit 99.03 to
                  the Annual Report on Form 10-K/A-1 of Travelers Group Inc.
                  for the fiscal year ended December 31, 1998 (File No. 1-9924).


         The total amount of securities authorized pursuant to any instrument
         defining rights of holders of long-term debt of the Company does not
         exceed 10% of the total assets of the Company and its consolidated
         subsidiaries. The Company will furnish copies of any such instrument to
         the Commission upon request.

         Copies of any of the exhibits referred to above will be furnished at a
         cost of $.25 per page (although no charge will be made for the 1998
         Annual Report on Form 10-K) to security holders who make written
         request therefor to Corporate Communications, Travelers Property
         Casualty Corp., One Tower Square, Hartford, Connecticut 06183.

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

*        Denotes a management contract or compensatory plan or arrangement
         required to be filed as an exhibit pursuant to Item 14(c) of Form 10-K.

+        Filed with Form 10-K/A-1.

Except as otherwise indicated, all exhibits were filed with the initial filing
of the Form 10-K.