Exhibit 5.1

                         [McGuireWoods LLP Letterhead]


                                 March 8, 2001



CSX Corporation
One James Center
901 East Cary Street
Richmond, VA 23219

Ladies and Gentlemen:

     We have advised CSX Corporation, a Virginia corporation (the "Company"), in
connection with (i) the Registration Statement on Form S-3 as amended (File No.
333-54700) (the "Registration Statement") filed by the Company with the
Securities and Exchange Commission for the purpose of registering under the
Securities Act of 1933, as amended, the Company's debt securities, debt
warrants, common stock, common stock warrants, preferred stock, preferred stock
warrants and depositary shares, from the sale of which the Company may receive
proceeds of up to $800,000,000, to be offered from time to time by the Company
on terms to be determined at the time of the offering and (ii) the issuance by
the Company of up to $500,000,000 aggregate principal amount of the Company's
6.75% Notes due 2011 (the "Notes") as described in the Company's Prospectus,
dated March 1, 2001, which is a part of the Registration Statement, and
Prospectus Supplement, dated March 8, 2001(the "Prospectus Supplement"), and
pursuant to an indenture dated as of August 1, 1990 between the Company and The
Chase Manhattan Bank, as trustee (the "Trustee"), as supplemented by a First
Supplemental Indenture dated as of June 15, 1991, a Second Supplemental
Indenture dated as of May 6, 1997 and a Third Supplemental Indenture dated as of
April 22, 1998 (the indenture, as so supplemented, is herein called the
"Indenture") and the Action of Authorized Pricing Officers adopted as of March
8, 2001 (the "Action of Authorized Pricing Officers"), and the public offering
of the Notes pursuant to an Underwriting Agreement, dated March 8, 2001 (the
"Underwriting Agreement"), among the Company and the Underwriters named on
Schedule I thereto. Capitalized terms used and not defined herein shall have the
meanings assigned to them in the Registration Statement or the Indenture.

     We have examined such corporate records, certificates and other documents,
and reviewed such questions of law, as we have considered necessary or
appropriate for the purpose of this opinion.

     On the basis of such examination and review, we advise you that, in our
opinion, when the Notes have been duly issued and sold in the manner
contemplated by the Registration Statement and the Prospectus Supplement, and
assuming due authentication thereof by the Trustee or the Authenticating Agent
in accordance with the provisions of the Indenture, as


March 8, 2001
Page 2


amended and supplemented, the Notes will constitute valid and legally binding
obligations of the Company, enforceable against the Company in accordance with
their terms, subject to bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium and similar laws of general applicability relating to
or affecting creditors' rights and to general equity principles.

     We hereby consent to the filing of this opinion as an exhibit to the
Company's Current Report on Form 8-K and the incorporation of this opinion by
reference in the Registration Statement and to references to us under the
heading "Legal Opinions" in the Registration Statement and the heading "Legal
Matters" in the Prospectus Supplement relating to the Notes.  We do not admit by
giving this consent that we are in the category of persons whose consent is
required under Section 7 of the Act.

                                            Very truly yours,

                                           /s/ McGuireWoods LLP