Exhibit 5



                                                                   March 2, 1999



Board of Directors
Union Carbide Corporation
39 Old Ridgebury Road
Danbury, CT  06817-0001

      Re:   Registration Statement on Form S-8 for Compensation
            DEFERRAL PROGRAM

Dear Sirs:

      Please refer to the Registration  Statement on Form S-8 (the "Registration
Statement")  under the Securities Act of 1933, as amended,  to be filed with the
Securities   and  Exchange   Commission  by  Union  Carbide   Corporation   (the
"Corporation")  relating to the registration of $50,000,000 of the Corporation's
deferred  compensation  obligations  (the "Deferred  Compensation  Obligations")
which are issuable under the Union Carbide  Compensation  Deferral  Program (the
"Plan").

      In  connection  with the opinion,  we have  examined and are familiar with
originals or copies,  certified or otherwise identified to our satisfaction,  of
such documents, corporate records, certificates of public officials and officers
of the  Corporation  and such other  instruments as we have deemed  necessary or
appropriate as a basis for the opinions expressed below.

      For  purposes  of this  opinion we have  assumed the  authenticity  of all
documents  submitted  to us as  originals,  the  conformity  to originals of all
documents   submitted  to  us  as  certified  or  photostatic  copies,  and  the
authenticity  of the  originals of all documents  submitted to us as copies.  We
have also assumed the legal capacity of all natural persons,  the genuineness of
all  signatures on all  documents  examined by us, the authority of such persons
signing on behalf of the parties  thereto other than the Corporation and the due
authorization,  execution and delivery of all  documents by the parties  thereto
other  than the  Corporation.  As to certain  factual  matters  material  to the
opinion  expressed  herein,  we have relied to the extent we deemed  proper upon
representations,  warranties  and statements as to matters of officers and other
representatives  of the Corporation.  Our opinion  expressed below is subject to
the  qualification  that we express no opinion as to any law other than the laws
of the State of New York and the federal  laws of the United  States of America.
Without  limiting  the  foregoing,  we express no  opinion  with  respect to the
applicability  thereto or effect of municipal laws or the rules,  regulations or
orders of any municipal agencies within any such state.

      Based upon the foregoing, we are of the opinion that:

      1. The Corporation  has been duly organized and is validly  existing under
the laws of the State of New York.

      2. The Plan  has  been  duly  adopted  by the  Board of  Directors  of the
Corporation.



Board of Directors                   -2-                           March 2, 1999



      3. When issued, the Deferred  Compensation  Obligations of the Corporation
will be  valid  and  binding  obligations  of the  Corporation,  enforceable  in
accordance  with their terms,  except as  enforcement  thereof may be limited by
bankruptcy,  insolvency  or other laws of general  applicability  relating to or
affecting enforcement of creditors' rights or by general equity principles.

      This opinion is limited to the specific issues  addressed  herein,  and no
opinion may be  inferred or implied  beyond that  expressly  stated  herein.  We
assume no  obligation to revise or  supplement  this opinion  should the present
laws of the  State of New  York or the  federal  laws of the  United  States  of
America be changed by legislative action, judicial decision or otherwise.

      We hereby  consent  to the  filing of this  letter as an  Exhibit 5 to the
Registration  Statement.  In giving such consent, we do not admit that we are in
the category of persons whose consent is required  under Section 7 of the Act or
the rules and regulations of the Commission promulgated thereunder.

      This  opinion is  furnished  to you in  connection  with the filing of the
Registration  Statement and is not to be used,  circulated,  quoted or otherwise
relied upon for any other purpose.


                                Very truly yours,


                                /s/ Kelley Drye & Warren LLP