EXHIBIT 5.1


                      [DAVIS POLK & WARDWELL LETTERHEAD]


                                                     September 25, 2003


MS Structured Asset Corp.
1585 Broadway
New York, New York 10036

     Re: CBT Series 2003-1 Units Trust

Ladies and Gentlemen:

     We have acted as special counsel to MS Structured Asset Corp. (the
"Depositor"), in connection with the formation of the CBT Series 2003-1 Units
Trust (the "Trust") and the issuance by the Trust of $25,000,000 aggregate unit
principal balance of Corporate Bond TRACERS(SM) Units (the "Units"). The Units
are being issued pursuant to the provisions of a Trust Agreement dated as of
September 25, 2003 (the "Trust Agreement"), between LaSalle Bank National
Association, as trustee (the "Trustee") and the Depositor, which Trust
Agreement, to the extent provided therein, incorporates by reference the
Standard Terms referenced therein. The Units are being offered pursuant to a
registration statement on Form S-3 (File No. 333-101155), herein referred to as
the "Registration Statement," and the related prospectus, as supplemented by
the prospectus supplement dated September 9, 2003, and as first filed with the
Securities and Exchange Commission pursuant to Rule 424(b) under the Securities
Act of 1933, as amended, herein referred to as the "Prospectus." Unless
otherwise defined herein, capitalized terms used herein shall have the meanings
ascribed thereto in the Trust Agreement.

     We have examined originals or copies, certified or otherwise identified to
our satisfaction, of such documents, corporate records, certificates of public
officials and other instruments as we have deemed necessary or advisable for the
purpose of rendering this opinion.

     We have assumed the conformity of the documents filed with the Commission
via the Electronic Data Gathering, Analysis and Retrieval System (EDGAR), except
for required EDGAR formatting changes, to physical copies of the documents
delivered to the Depositor and submitted for our examination.



MS Structured Asset Corp.
September 25, 2003
Page 2


     In rendering the opinions expressed below, we have assumed that: (i) the
copies of all documents that we have reviewed conform to the originals thereof,
and the signatures on all documents that we have examined are genuine; and (ii)
that the Trust Agreement has been duly authorized and approved by, and validly
executed by duly authorized representatives of, the parties thereto. We have
also relied, without independent verification or investigation, on the
representation and warranty of the Depositor in the Trust Agreement to the
effect that the execution and delivery of the Trust Agreement, and the
Depositor's performance of or compliance with the terms of the Trust Agreement,
will not violate any term or provision of the articles of incorporation or
by-laws of the Depositor or constitute a default (or an event which, with notice
or lapse of time, or both, would constitute a default) under, or result in the
breach or acceleration of, any material contract, agreement or other instrument
to which the Depositor is a party or by which the Depositor or any of its assets
is bound, or constitute a violation of any order or decree of any court or any
order or regulation of any federal, state, municipal or governmental agency
having jurisdiction over the Depositor or its properties.

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

     1. Assuming, without independent investigation and with your consent, that
the Trust Agreement has been duly authorized and executed by each of the
parties thereto, the Trust Agreement is a valid and binding agreement of the
Depositor, enforceable in accordance with its terms except as limitations on
fiduciary liability thereunder may be limited by applicable law and except as
the enforceability thereof (i) may be limited by bankruptcy, insolvency,
reorganization, liquidation, moratorium and other similar laws affecting
creditors rights generally and (ii) is subject to general principles of equity,
regardless of whether such enforceability is considered in a proceeding in
equity or at law; and

     2. Assuming, without independent investigation and with your consent, that
the Trust Agreement has been duly authorized and executed by the parties
thereto, and that the Units have been duly authorized by the Depositor, when the
Units have been duly executed and authenticated in accordance with the terms of
such Trust Agreement and duly delivered to and paid for by the purchasers
thereof in the manner described in the Prospectus, the Units will be entitled to
the benefits of such Trust Agreement and will constitute an undivided beneficial
ownership interest in the Trust enforceable in accordance with their terms
except as the enforceability thereof (i) may be limited by bankruptcy,
insolvency, reorganization, liquidation, moratorium and other similar laws
affecting creditors rights generally and (ii) is subject to general principles
of equity, regardless of whether such enforceability is considered in a
proceeding in equity or at law.



MS Structured Asset Corp.
September 25, 2003
Page 3


     We are members of the Bar of the State of New York and our opinion is
limited to the laws of the State of New York and the Federal laws of the United
States.

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement. In addition, we consent to the reference to us under the
caption "Legal Matters" in the Prospectus. The issuance of such a consent does
not concede that we are an "Expert" for the purposes of the Securities Act of
1933.

     We are furnishing this opinion letter to the Depositor, solely for the
benefit of the Depositor in its capacity as such.

                                           Very truly yours,

                                           /s/ Davis Polk & Wardwell