Exhibit 23-a        Consent of Arthur Andersen, LLP, Independent Accountants


CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

As independent  public  accountants,  we hereby consent to the  incorporation by
reference in this  registration  statement of our report dated  January 27, 2000
included in KeySpan  Corporation's  Form 10- K for the year ended  December  31,
1999.

/s/ ARTHUR ANDERSEN LLP
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ARTHUR ANDERSEN LLP


August 14, 2000
New York, New York


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Exhibit 23-b        Consent of Ernst & Young, LLP, Independent Auditors


CONSENT OF INDEPENDENT AUDITORS

     We consent to the reference to our firm under the caption  "Experts" in the
     Registration  Statement on Form S-3 and the related  Prospectus  of KeySpan
     Corporation for the registration of  $1,650,000,000  of debt securities and
     to the incorporation by reference therein 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
     KeySpan  Corporation  (formerly  known as MarketSpan  Corporation)  for the
     transition  period from April 1, 1998 to December 31, 1998,  filed with the
     Securities and Exchange Commission.


/S/ ERNST & YOUNG LLP
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ERNST & YOUNG LLP

August 14, 2000
Melville, New York



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