Exhibit 32.1



                              CERTIFICATION OF THE

                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER

                             PURSUANT TO SECTION 906

                        OF THE SARBANES-OXLEY ACT OF 2002


     In  connection  with the  Annual  Report  on Form  10-K for the year  ended
December 31, 2005 of KeySpan Corporation (the "Corporation"),  as filed with the
Securities and Exchange Commission on the date hereof (the "Report"),  I, Robert
B. Catell,  Chairman and Chief Executive  Officer of the  Corporation,  certify,
pursuant to 18 U.S.C.  Section 1350,  as adopted  pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002, that:

     (1)  The Report fully  complies with the  requirements  of Section 13(a) or
          15(d) of the Securities Exchange Act of 1934, as amended; and

     (2)  The  information  contained  in the  Report  fairly  presents,  in all
          material respects,  the financial  condition and results of operations
          of the Company.


Date:             February 28, 2006


                                              /s/ Robert B. Catell
                                              --------------------
                                              Robert B. Catell
                                              Chairman of the Board of Directors
                                              and Chief Executive Officer