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 June 30, 2003 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: August 6, 2003

Note: A signed original of this written statement required by Section 906 has
been provided to KeySpan Corporation and will be retained by KeySpan Corporation
and furnished to the Securities and Exchange Commission or its staff upon
request.