Exhibit 5



                                                 July 5, 2001



Merrill Lynch & Co., Inc.
4 World Financial Center
New York, New York 10080

Dear Sirs:

     We have  acted  as  counsel  for  Merrill  Lynch & Co.,  Inc.,  a  Delaware
corporation  (the  "Company"),  in connection  with the proposed filing with the
Securities and Exchange Commission expected to be made on or about July 5,  2001
under the  Securities Act of 1933, as amended,  of a  Registration  Statement on
Form  S-8  (the  "Registration   Statement")  for  the  purpose  of  registering
25,000,000  shares of Common Stock,  par value  $1.33 1/3  per share  (including
Preferred  Stock Purchase  Rights) (the "Common  Stock") of Merrill Lynch & Co.,
Inc.  that may be sold in  connection  with the Merrill  Lynch & Co.,  Inc. 1986
Employee  Stock Purchase Plan (the "Plan").  In such capacity,  we have examined
the Restated  Certificate of Incorporation and By-Laws of the Company, the Plan,
and  such  other  documents  of the  Company  as we  have  deemed  necessary  or
appropriate for the purposes of the opinion expressed herein.

     Based upon the foregoing, we advise you that, in our opinion, the shares of
Common Stock sold in connection with the Plan will be legally issued, fully paid
and nonassessable.

     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/ Sidley Austin Brown & Wood LLP