Exhibit 5

(Foley & Lardner LLP letterhead)

  November 2, 2011 ATTORNEYS AT LAW 777 EAST WISCONSIN AVENUE MILWAUKEE, WI  53202-5306 414.271.2400 TEL 414.297.4900 FAX www.foley.com     CLIENT/MATTER NUMBER 086120-0861

Wisconsin Public Service Corporation

700 North Adams Street

Green Bay, Wisconsin 54307-9001

Ladies and Gentlemen:

We have acted as counsel for Wisconsin Public Service Corporation, a Wisconsin corporation (the “Company”), in connection with the preparation of a Registration Statement on Form S-3 (the “Registration Statement”), including the prospectus constituting a part thereof (the “Prospectus”), to be filed by the Company with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Securities Act”).  The Registration Statement and the Prospectus relate to the proposed issuance and sale from time to time pursuant to Rule 415 under the Securities Act of up to $500,000,000 of senior debt securities of the Company (the “Securities”), to be issued under an Indenture dated as of December 1, 1998 (the “Indenture”), between the Company and U.S. Bank National Association (successor to Firstar Bank Milwaukee, N.A., National Association), as trustee.  The Prospectus provides that it will be supplemented in the future by one or more supplements to such Prospectus (each, a “Prospectus Supplement”).

We have examined the Registration Statement, the Restated Articles of Incorporation of the Company, the By-laws of the Company and the Indenture.  We have also examined the corporate proceedings taken by the Board of Directors of the Company to authorize the filing of the Registration Statement and the issuance of the Securities, as well as such other documents, records and instruments as we have deemed necessary or appropriate for purposes of rendering this opinion.  In addition, we are familiar with the proceedings by which such instruments and the transactions contemplated thereby were authorized by the Company.  In all such examinations, we have assumed the genuineness of all signatures, the authenticity of all documents, certificates and instruments submitted to us as originals and the conformity with the originals of all documents submitted to us as copies.  We have, among other things, relied upon certificates of public officials and, as to various factual matters, certificates of officers of the Company.

Based upon and subject to the foregoing, and assuming that (a) the Registration Statement and any amendments thereto (including post-effective amendments) will have become effective and comply with all applicable laws; (b) the Registration Statement will be effective and will comply with all applicable laws at the time the Securities are offered or issued as contemplated by the Registration Statement; (c) a Prospectus Supplement, pricing supplement or term sheet will have been prepared and filed with the Securities and Exchange Commission describing the Securities offered thereby that complies with all applicable laws; (d) all Securities

November 2, 2011

Page 2

will be issued and sold in compliance with applicable federal and state securities laws and in the manner stated in the Registration Statement and the appropriate Prospectus Supplement; and (e) a definitive purchase, underwriting, agency or similar agreement with respect to any Securities offered or issued will have been duly authorized and validly executed and delivered by the Company and the other parties thereto, we are of the opinion that:

1.The Company is a validly existing corporation under the laws of the State of Wisconsin.

2.When (A) the Board of Directors of the Company, a duly constituted and acting committee thereof or a duly authorized, constituted and acting senior officer or officers of the Company (such Board of Directors, committee or senior officer(s) being hereinafter referred to as the “Board”) has taken all necessary corporate action to approve the issuance and terms of the Securities, the terms of the offering thereof and related matters; (B) the issuance of the Securities has been duly authorized by the Public Service Commission of Wisconsin; (C) the supplemental indentures relating to the Securities that amend and supplement the Indenture (the “Supplemental Indentures”) have been executed by the proper parties and have been delivered; and (D) the Securities have been duly executed, authenticated, issued and delivered upon payment of the consideration therefore provided for therein, in accordance with the provisions of the Indenture and the Supplemental Indentures and the applicable definitive purchase, underwriting, agency or similar agreement approved by the Board, such Securities will be validly issued and will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their terms (subject to applicable bankruptcy, insolvency, reorganization, fraudulent conveyance, moratorium or other similar laws affecting the enforceability of creditors’ rights generally and to court decisions with respect thereto, and subject to general principles of equity, regardless of whether such enforceability is considered in a proceeding in equity or at law).

We hereby consent to the filing of this opinion as Exhibit 5 to the Registration Statement and to the reference to our firm under the heading “Legal Matters” in the Prospectus forming a part thereof.

Very truly yours,

/s/ Foley & Lardner LLP

FOLEY & LARDNER LLP