Exhibit 5.1

                                         March 14, 2000


Magna Entertainment Corp.
285 West Huntington Drive
Arcadia, California  91007

     Re:  Registration Statement on Form S-8
          8,000,000 Shares of Class A Subordinate Voting Stock
          ----------------------------------------------------

Ladies and Gentlemen:

     We refer to the Registration Statement on Form S-8 (the "Registration
Statement") being filed by Magna Entertainment Corp., a Delaware corporation
(the "Company"), with the Securities and Exchange Commission under the
Securities Act of 1933, as amended, relating to the registration of an aggregate
of 8,000,000 shares of Class A Subordinate Voting Stock, par value $.01 per
share, of the Company (the "Registered Common Stock"), to be issued under the
Magna Entertainment Corp. Long-Term Incentive Plan (the "Plan").

     In connection with the proposed issuance of the Registered Common Stock, we
have examined such records, documents and questions of law, and satisfied
ourselves as to such matters of fact, as we have considered relevant and
necessary as a basis for this opinion.

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

     1. The Company is validly existing as a corporation under the laws of the
State of Delaware.

     2. Each share of the Registered Common Stock which is issued pursuant to
the Plan will constitute a share of common stock of the Company that has been
duly authorized and validly issued and is fully paid and non-assessable when:
(i) the Registration Statement shall have become effective under the Securities
Act; (ii) the Company's Board of Directors or a duly authorized committee
thereof shall have duly adopted final resolutions authorizing the issuance and
sale of such share as contemplated by the Plan; and (iii) a certificate
representing such share shall have been duly executed, countersigned and
registered and duly delivered upon payment of the agreed consideration therefor
(not less than the par value thereof) determined in accordance with the terms of
the Plan.

     This opinion is limited to the General Corporation Law of the State of
Delaware.

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement.

                                         Very truly yours,


                                         /s/ Sidley & Austin