EXHIBIT 5.1



                                  June 25, 1999

Equitable Resources, Inc.
One Oxford Centre, Suite 3300
301 Grant Street
Pittsburgh, PA 15219

Gentlemen:

            I am the Vice President,  General Counsel and Secretary to Equitable
Resources, Inc., a Pennsylvania corporation (the "Company"), and I have acted in
such capacity in connection  with the  Registration  Statement on Form S-8 being
filed with the Securities and Exchange Commission (the "Registration Statement")
for the purpose of  registering  under the  Securities  Act of 1933, as amended,
300,000  shares of Common  Stock,  no par  value,  which may be issued  upon the
exercise  of stock  options  and other  stock  awards  under the 1999  Equitable
Resources,  Inc.  Non-Employee  Directors' Stock Incentive Plan (the "Plan"). In
such connection,  I have examined the originals, or copies thereof identified to
my  satisfaction,  of such  corporate  records  of the  Company  and such  other
documents,   records,  opinions  and  papers  as  I  have  deemed  necessary  or
appropriate in order to give the opinions hereinafter set forth.

            I understand that, prior to any sale or distribution of Common Stock
under the Plan, the Registration  Statement will have become effective under the
Securities  Act of 1933,  the  Company's  shareholders  will have  approved  the
implementation of the Plan and the Pennsylvania  Public Utility Commission shall
have issued an order approving the Company's  issuance of the Common Stock under
the Plan.

            Based on the foregoing, I advised you that in my opinion:

1.          The Company  has been duly  organized  and is a validly  existing
corporation under the laws of the Commonwealth of Pennsylvania;

2. The 300,000 shares of Common Stock which are being  registered and which have
been  authorized for issuance in accordance with the Plan, are, or will be, when
sold in accordance with the provisions of the Plan,  legally issued,  fully paid
and non-assessable.

            I hereby  consent to the filing of my opinion as Exhibit  5.1 to the
Registration Statement.

                                        Very truly yours,



                                   /s/ JOHANNA G. O'LOUGHLIN
                                       Johanna G. O'Loughlin
                                  Vice President, General Counsel
                                           and Secretary