DONNA M. LEVY                         Baltimore Gas and Electric Company
        Counsel                               P. O. Box 1475
                                              Baltimore, MD  21203-1475
                                              410 234-5598   FAX 410  234-7168
                                              donna.m.levy@bge.com
 

                                                                   Exhibit 5 (a)



March 25, 1999


Constellation Energy Group, Inc.
c/o David A. Brune
39 W. Lexington Street
Baltimore, MD 21201

Gentlemen:

         This opinion is provided in connection with Post-Effective Amendment
No. 1 ("Post-Effective Amendment") filed by Constellation Energy Group, Inc.
("Constellation Energy") to the Registration Statements filed by Baltimore Gas
and Electric Company ("BGE") with the Securities and Exchange Commission
("Commission") under the Securities Act of 1933 (the "Securities Act").
Registration Statement No. 33-57658 filed by BGE regards, among other things,
the proposed issuance of up to 2,000,000 shares of BGE common stock and
Registration Statement No. 333-59601 filed by BGE regards, among other things,
the proposed issuance of up to 3,000,000 shares of BGE common stock
(collectively, the "Common Stock").

         Pursuant to an Agreement and Plan of Share Exchange dated February 19,
1999, between Constellation Energy and BGE, upon the occurrence of certain
events all of the outstanding common stock of BGE will be exchanged, on a
one-for-one basis, for common stock of Constellation Energy. As a result of the
share exchange, Constellation Energy will become a successor to BGE and will be
authorized to succeed BGE as a registrant of its various effective registration
statements filed with the Commission. In anticipation of the consummation of the
share exchange, Constellation Energy is filing this Post-Effective Amendment in
regard to its Common Stock to be offered upon effectiveness of the share
exchange.

         I am an attorney in the Corporate Unit of the legal department of BGE.
BGE is a shareholder of Constellation Energy, and Constellation Energy has
requested that I provide this opinion. Constellation Energy is a Maryland
corporation. In connection with this opinion I, together with other attorneys
assisting me, have considered, among other things: (1) the current articles of
incorporation of Constellation Energy, as amended, and a form of amended and
restated articles of incorporation of Constellation Energy (the "Charter" ) to
be filed and effective upon consummation of the share exchange; (2) the current
by-laws of Constellation Energy, and a form of by-laws of Constellation Energy
to be adopted effective upon consummation of the share exchange (the "By-laws");
(3) the corporate proceedings for the approval and issuance of the Common Stock;
(4) the Post-Effective Amendment; (5) the agency agreement (including the
standard purchase provisions) filed as an exhibit to the Registration Statement
(the "Purchase Agreement"); (6) the provisions of the Public Utility Holding
Company Act of 1935 (the "1935 Act"); and (7) such other documents,
transactions, and matters of law as we deemed necessary in order to render this
opinion.




         This opinion is subject to: (1) the share exchange becoming effective
and the filing with the appropriate State authority, and effectiveness of,
Constellation Energy's Charter; (2) the proper adoption by Constellation
Energy's Board of Directors of the By-Laws; and (3) the Registration Statement
becoming effective under the Securities Act of 1933.

         It is my opinion that when there has been compliance with the
Securities Act and the applicable state securities laws, the Common Stock to be
sold by Constellation Energy, when issued, delivered, and paid for in the manner
described in the form of Purchase Agreement will be legally issued, fully paid
and nonassessable.

         I express no opinion as to the law of any jurisdiction other than the
law of the State of Maryland and the law of the United States of America. The
opinion expressed herein concerns only the effect of the law (excluding the
principles of conflicts of law) of the State of Maryland and the United States
of America as currently in effect.

         This opinion is provided to you solely in connection with the filing of
the Post-Effective Amendment and may not be relied upon by, or quoted to, any
other person or entity, in whole or in part, without my prior written consent.

         I hereby consent to the filing of this opinion as an exhibit to the
Post-Effective Amendment and to the references to me in the Post-Effective
Amendment (and any amendments thereto) or the prospectus constituting a part of
the Post-Effective Amendment (and any amendments or supplements thereto). In so
doing, I do not admit that I am in the category of persons whose consent is
required under Section 7 of the Securities Act or the rules and regulations of
the Commission promulgated thereunder.

                                                     Very truly yours,

                         

                                                     /s/ Donna M. Levy
                                                     ------------------
                                                         Donna M. Levy