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 of KeySpan  Corporation (the "Corporation")
for the year ended  December 31, 2004 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.


                                    /s/Robert B. Catell
                                    ------------------------------
                                    Name: Robert B. Catell
                                    Title: Chairman and Chief Executive Officer
                                    Date: March 1, 2005