[Letterhead of Brown & Wood LLP.] 

                                                                       Exhibit 5

                               November 24, 1998

Merrill Lynch & Co., Inc.
World Financial Center
North Tower
New York, New York 10281-1334

Ladies and Gentleman:

     We have acted as your counsel and are familiar with the corporate
proceedings had in connection with the proposed issuance and sale by Merrill
Lynch & Co., Inc. (the "Company") of up to 408,000 shares of common stock, par 
value $1.33 1/3 per share, of the Company (the "Common Stock").

     We have examined such documents and records as we deemed appropriate,
including the following:

     (a)   a copy of the Restated Certificate of Incorporation of the Company,
           certified by the Secretary of State of the State of Delaware.

     (b)   a copy of the By-Laws of the Company, as amended, certified by the
           Secretary of the Company to be a true and correct copy.

     (c)   a copy of the Company's Registration Statement on Form S-3
           registering the Common Stock of the Company filed on the date hereof
           (the "Registration Statement"), and

     (d)   a specimen of the certificate representing the Common Stock in the
           form filed or incorporated by reference as an exhibit to the
           Registration Statement.

     Based upon the foregoing and upon such further investigation as we deem
relevant in the premises, we are of the opinion:

     1.    The Company has been duly incorporated under the laws of the State 
of Delaware.

     2.    The Common Stock, when issued and delivered as contemplated in the
Registration Statement, will be duly authorized, validly issued, fully paid and
non-assessable.

     We consent to the filing of this opinion as an exhibit to the Registration 
Statement and to the use of our name wherever appearing in the Registration 
Statement and any amendment thereto.

           
                                    Very truly yours,

                                    /s/BROWN & WOOD LLP