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  Quarterly   Report  of  KeySpan   Corporation   (the
"Corporation")  for the  quarter  ended  September  30,  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: November 4, 2004