8-K

                      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)
                             September 27, 2000



                           UNION CARBIDE CORPORATION
           (Exact name of registrant as specified in its charter)



    New York                     1-1463                       13-1421730
(State or other         (Commission File Number)             (IRS Employer
jurisdiction of                                           Identification No.)
incorporation)





              39 Old Ridgebury Rd, Danbury, CT           06817-0001
          (Address of principal executive offices)       (Zip code)



                        Registrant's telephone number,
                      including area code 203-794-2000


                                Not applicable
        (Former name or former address, if changed since last report)






Item 5.  OTHER EVENTS


         With reference to the Agreement and Plan of Merger, dated as of
         August 3, 1999, among Union Carbide Corporation, a New York
         corporation ("Union Carbide"), The Dow Chemical Company, a Delaware
         corporation ("Dow Chemical"), and Transition Sub Inc., a Delaware
         corporation, Dow Chemical and Union Carbide have entered into a
         letter agreement filed herewith as Exhibit 99, which letter agreement
         was sent by Union Carbide to Dow Chemical on September 27, 2000 and
         executed by Dow Chemical on September 27, 2000.



Item 7.  FINANCIAL STATEMENTS AND EXHIBITS

         (C)  Exhibits.

              99.  Letter Agreement, dated September 27, 2000, with reference
                   to the Agreement and Plan of Merger, dated as of August 3,
                   1999, among Union Carbide Corporation, a New York
                   corporation, The Dow Chemical Company, a Delaware
                   corporation, and Transition Sub Inc., a Delaware
                   corporation.




                                      - 2 -





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.


Date:  September 27, 2000



                                        UNION CARBIDE CORPORATION

                                        /s/ J. Macdonald
                                        J. Macdonald
                                        Assistant Secretary


                                      - 3 -



                                 EXHIBIT INDEX

Exhibits

99.  Letter Agreement, dated September 27, 2000, with reference to the
     Agreement and Plan of Merger, dated as of August 3, 1999, among Union
     Carbide Corporation, a New York corporation, The Dow Chemical Company,
     a Delaware corporation, and Transition Sub Inc., a Delaware corporation.



                                      - 4 -

EX-99

                                                           EXHIBIT 99



                                   September 27, 2000


VIA FAX AND OVERNIGHT MAIL


The Dow Chemical Company
2030 Dow Center
Midland, MI  48674

Attention:  Chief Executive Officer

Dear Sirs:

     Reference is made to the Agreement and Plan of Merger,
dated as of August 3, 1999 (the "Agreement"), among Union
Carbide Corporation, a New York corporation, The Dow
Chemical Company, a Delaware corporation, and Transition Sub
Inc., a Delaware corporation.

     Each of the parties hereto agrees that it will not
exercise any right it may have to terminate the Agreement
under Section 8.2(i) of the Agreement prior to December 31,
2000.  Notwithstanding anything to the contrary in the
foregoing, this letter agreement shall not in any way limit,
restrict or affect any of the other rights of the parties
(relating to termination of the Agreement or otherwise)
under the Agreement.



                                    -2-




     If the foregoing is acceptable to you, please execute a
copy of this letter agreement in the space below, whereupon
this instrument will constitute a binding agreement among
us.

                               Very truly yours,

                               UNION CARBIDE CORPORATION

                               By: /s/ B.D. Fitzgerald
                                   Name:   B.D. Fitzgerald
                                   Title:  Vice President,
                                           General Counsel
                                           and Secretary



ACCEPTED AND AGREED as
of the date first written above:

THE DOW CHEMICAL COMPANY

By: /s/ J.P. Reinhard
    Name:   J. P. Reinhard
    Title:  Executive Vice President and
            Chief Financial Officer