Consent of Independent Auditors

We consent to the  incorporation by reference in the  Registration  Statement on
Form S-8 (No. 333-53765),  relating to KeySpan  Corporation's  Employee Discount
Stock  Purchase  Plan  and in  the  related  Prospectus,  and  the  Registration
Statement on Form S-3 (No. 333-53657),  relating to the issuance of Common Stock
under KeySpan Corporation's  Investor Program and in the related Prospectus,  of
our report dated May 22,  1998,  with respect to the  financial  statements  and
schedule of Long Island  Lighting  Company  included in the Annual  Report (Form
10-K),  as amended,  of MarketSpan  Corporation  for the year ended December 31,
1998,  which report is included in Exhibit 99.1 to and incorporated by reference
in the  Current  Report on Form 8-K  dated  December  2,  1999,  filed  with the
Securities and Exchange Commission.

                                                       /S/ERNST & YOUNG LLP



December 2, 1999
Melville, New York






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