EXHIBIT 5.1



                                                             
                                   BAKER & BOTTS
 AUSTIN                                L.L.P.
  BAKU                             ONE SHELL PLAZA
 DALLAS                             910 LOUISIANA
 LONDON                        HOUSTON, TEXAS 77002-4995           TELEPHONE: (713) 229-1234
 MOSCOW                                                            FACSIMILE: (713) 229-1522
 NEW YORK
WASHINGTON






016119.0238                                          June 29, 1999


Lyondell Chemical Company
Lyondell Chemical Worldwide, Inc.
Lyondell Chemical Nederland, Ltd.
One Houston Center
1221 McKinney, Suite 700
Houston, Texas 77010

Gentlemen:

          As set forth in the Registration Statement on Form S-4 (the
"Registration Statement") to be filed by Lyondell Chemical Company, a Delaware
corporation ("Lyondell"), Lyondell Chemical Worldwide, Inc., a Delaware
corporation ("LCW"), and Lyondell Chemical Nederland, Ltd., a Delaware
corporation ("LCNL") (together, the "Co-registrants"), with the Securities and
Exchange Commission (the "Commission") under the Securities Act of 1933, as
amended (the "Act"), relating to the registration under the Act of $900 million
aggregate principal amount of 9 5/8% Senior Secured Notes, Series A, Due 2007,
$1 billion aggregate principal amount of 9 7/8% Senior Secured Notes, Series B,
Due 2007 and $500 million aggregate principal amount of 10 7/8% Senior
Subordinated Notes Due 2009 (collectively, the "New Notes") to be offered by
Lyondell in exchange (the "Exchange Offers") for like principal amounts of its
issued and outstanding unregistered 9 5/8% Senior Secured Notes, Series A, Due
2007, 9 7/8% Senior Secured Notes, Series B, Due 2007 and 10 7/8% Senior
Subordinated Notes Due 2009 (collectively, the "Outstanding Notes") and the
issuance of the related guarantees of the New Notes by LCW and LCNL (the
"Guarantees"), we are passing upon certain legal matters in connection with the
New Notes and the Guarantees for Lyondell, LCW and LCNL. The New Notes are to be
issued under indentures dated as of May 17, 1999 (the "Indentures") among
Lyondell, the Subsidiary Guarantors party thereto and The Bank of New York, as
trustee. At your request, this opinion is being furnished to you for filing as
Exhibit 5.1 to the Registration Statement.

          In our capacity as counsel to Lyondell, LCW and LCNL in connection
with the matters referred to above, we have examined the Certificate of
Incorporation and Bylaws of Lyondell, LCW and LCNL, each as amended to date, and
originals, or copies certified or otherwise identified, of corporate records of
Lyondell, LCW and LCNL, including minute books of Lyondell, LCW and LCNL as
furnished to us by Lyondell, LCW and LCNL, certificates of public officials and
of representatives of Lyondell, LCW and LCNL, statutes and other instruments and
documents as a basis for the opinions hereinafter expressed.  In giving such
opinions, we have relied upon certificates of officers of Lyondell, LCW and LCNL
with respect to the accuracy of the material



Lyondell Chemical Company
Lyondell Chemical Worldwide, Inc.
Lyondell Chemical Netherland, Ltd.         -2-                  June 28, 1999

factual matters contained in such certificates. We have assumed that all
signatures on documents examined by us are genuine, all documents submitted to
us are authentic and all documents submitted as certified or photostatic copies
conform to the originals thereof.

          Based on our examination as aforesaid, we are of the opinion that,
when each series of New Notes has been duly executed, authenticated and
delivered in accordance with the provisions of the applicable Indenture and
issued in exchange for the corresponding series of Outstanding Notes pursuant
to, and in accordance with the terms of, the applicable Exchange Offer as
contemplated in the Registration Statement, (i) the New Notes will constitute
legal, valid and binding obligations of Lyondell, LCW and LCNL enforceable
against Lyondell, LCW and LCNL in accordance with their terms, except to the
extent that the enforceability thereof may be limited by bankruptcy, fraudulent
conveyance, insolvency, reorganization, moratorium or other laws relating to or
affecting creditors' rights generally and by general principles of equity
(regardless of whether such enforceability is considered in a proceeding in
equity or at law) and (ii) the Guarantees will be entitled to the benefits of
the applicable Indenture and will constitute legal, valid and binding
obligations of LCW and LCNL enforceable against LCW and LCNL in accordance with
their terms, except to the extent that the enforceability thereof may be limited
by bankruptcy, fraudulent conveyance, insolvency, reorganization, moratorium or
other laws relating to or affecting creditors' rights generally and by
principles of equity (regardless of whether such enforceability is considered in
a proceeding in equity or at law).

          We hereby consent to the filing of this opinion of counsel as Exhibit
5 to the Registration Statement and to the reference to our Firm under the
heading "Legal Matters" in the prospectus forming a part of the Registration
Statement. In giving this consent, we do not hereby 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 thereunder.

                                    Very truly yours,

                                    BAKER & BOTTS, L.L.P.



SAM/ER