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,
3,000,000  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. Long-Term  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  3,000,000  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  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