Exhibit 32.1

Written Statement of the Chief Executive Officer and Chief Financial Officer

Pursuant to 18 U.S.C. Section 1350

Solely for the purposes of complying with 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, we, the undersigned Chief Executive Officer and Chief Financial Officer of Integrys Energy Group, Inc. (the “Company”), hereby certify, based on our knowledge, that the Annual Report on Form 10-K of the Company for the year ended December 31, 2007 (the “Report”) fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934 and that information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ Larry L. Weyers                                                                           

Larry L. Weyers

President and Chief Executive Officer

/s/ Joseph P. O'Leary                                                                           

Joseph P. O'Leary

Senior Vice President and Chief Financial Officer

Date:  February 28, 2008

This certification accompanies this Report pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and shall not be deemed filed by Integrys Energy Group, Inc. for purposes of Section 18 of the Securities Exchange Act of 1934, as amended.

A signed original of this written statement required by Section 906 has been provided to Integrys Energy Group, Inc. and will be retained by Integrys Energy Group, Inc. and furnished to the Securities and Exchange Commission or its staff upon request.