SCHEDULE 14A
                                (RULE 14A-101)

                   INFORMATION REQUIRED IN PROXY STATEMENT

                            SCHEDULE 14A INFORMATION
                PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE
                SECURITIES EXCHANGE ACT OF 1934 (AMENDMENT NO. )

Filed by the Registrant [X]

Filed by a Party other than the Registrant [ ]


[ ]     Preliminary Proxy Statement          [ ]  Confidential, for Use of the
                                                  Commission Only (as permitted
                                                  by Rule 14a-6(e)(2))
[ ]     Definitive Proxy Statement

[X]     Definitive Additional Materials

[ ]     Soliciting Material Pursuant to Rule 14a-11(c) or Rule 14a-12


                          UNION CARBIDE CORPORATION
               (Name of Registrant as Specified in Its Charter)


  (Name of Person (s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

[X]   No fee required.

[ ]   Fee computed on table below per Exchange Act Rule 14a-6(i) (1) and 0-11.

          (1)  Title of each class of securities to which transaction applies:

          (2)  Aggregate number of securities to which transaction applies:

          (3)  Per unit price or other underlying value of transaction 
               computed pursuant to Exchange Act Rule 0-11 (set forth the 
               amount on which the filing fee is calculated and state how it was
               determined):

          (4)  Proposed maximum aggregate value of transaction:

          (5)  Total fee paid:

[ ]     Fee paid previously with preliminary materials:

[ ]     Check box if any part of the fee is offset as provided by Exchange Act
        Rule 0-11 (a) (2) and identify the filing for which the offsetting 
        fee was paid previously.  Identify the previous filing by 
        registration statement number, or the Form or Schedule and the date 
        of its filing.

          (1)  Amount Previously Paid:

          (2)  Form, Schedule or Registration Statement No.:

          (3)  Filing Party:

          (4)  Date Filed:




UNION CARBIDE CORPORATION 39 OLD RIDGEBURY ROAD, DANBURY, CT 06817-0001
                                                 PHONE:  [203] 794-5023
                                                   FAX:  [203] 794-4423

BRUCE D. FITZGERALD
VICE PRESIDENT, GENERAL COUNSEL & SECRETARY
(ADMITTED IN NEW YORK ONLY)


                                                April 9, 1999


Dear Carbider:

          By now you have received a copy of Union Carbide's 1998 Annual 
Report and the Proxy Statement for the corporation's annual meeting of 
stockholders to be held on April 28, 1999.

          YOUR  VOTE IS PARTICULARLY IMPORTANT BECAUSE YOUR BOARD OF DIRECTORS 
UNANIMOUSLY RECOMMENDS THAT SHAREHOLDERS VOTE AGAINST PROPOSAL 3 ON THIS 
YEAR'S AGENDA.  This proposal was made by State of Wisconsin Investment Board 
("SWIB").  It is intended to significantly limit the way the Board of 
Directors can adopt and administer shareholder rights plans. 

          Rights plans of the kind advocated by SWIB encourage hostile 
takeover attempts, while denying the Board a tool it needs to get the best 
deal for all Carbiders who have worked so long and hard to maximize the value 
of the investment we have made in our company.  This arrangement might be 
favored by short term speculators, but is particularly unwise for investors 
aiming to realize full shareholder value.  Only the Board can negotiate 
effectively to maximize shareholder value and protect the interests of 
shareholders, employees and customers.

          WE URGE YOU, THEREFORE, TO VOTE AGAINST PROPOSAL 3.  If you have 
already voted in favor of Proposal 3, we ask you to reconsider. Enclosed is a 
duplicate proxy card.  You have the option of returning a completed card in 
the enclosed envelope or voting by telephone or over the Internet as 
instructed on the card.  If you have voted AGAINST, we thank you for your 
support.

          YOUR VOTE COUNTS.  The trustees of the Savings and Investment 
Program and the Employee Stock Ownership Plan (ESOP) are required to vote all 
shares in the plans (nearly 19.5 million shares in all) in proportion to the 
votes received from participants.  Thus, if you fail to vote, you give more 
leverage to those who vote differently than you would.  

          PLEASE VOTE.  PLEASE VOTE AGAINST PROPOSAL 3.

                                                Sincerely, 

                                                /s/ Bruce D. Fitzgerald
                                                Bruce D. Fitzgerald

BDF:dg