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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 8-K

                                 CURRENT REPORT
     PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934


        Date of Report (Date of earliest event reported): MARCH 30, 2006


                         NORTHERN BORDER PARTNERS, L.P.
             (Exact name of registrant as specified in its charter)

   DELAWARE                         1-12202                     93-1120873
(State or other                   (Commission                  (IRS Employer
jurisdiction of                   File Number)               Identification No.)
 incorporation)

          13710 FNB PARKWAY
           OMAHA, NEBRASKA                                       68154-5200
(Address of principal executive offices)                         (Zip Code)

       Registrant's telephone number, including area code: (402) 492-7300


                                 Not Applicable
       ------------------------------------------------------------------
         (Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions:

[ ]  Written communications pursuant to Rule 425 under the Securities Act
     (17 CFR 230.425)

[ ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act
     (17 CFR 240.14a-12)

[ ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
     Exchange Act (17 CFR 240.14d-2(b))

[ ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
     Exchange Act (17 CFR 240.13e-4(c))


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ITEM 1.01  ENTRY INTO A MATERIAL DEFINITIVE AGREEMENT


Purchase of Membership Interests in Guardian Pipeline, L.L.C.

         Northern Border Intermediate Limited Partnership ("NBILP") entered into
a Purchase and Sale Agreement (the "PSA") with Wisconsin Energy Corporation
("WEC") and WPS Investments, LLC ("WPS"), dated as of March 30, 2006, pursuant
to which NBILP has agreed to purchase all of the membership interests (the
"Membership Interests") owned by WEC and WPS in Guardian Pipeline, L.L.C.
("Guardian") in exchange for an aggregate cash amount of approximately $77
million, subject to certain adjustments as set forth in the PSA. The Membership
Interests owned by WEC and WPS in Guardian collectively represent 66-2/3% of the
total outstanding Membership Interests in Guardian. Viking Gas Transmission
Company, an indirect subsidiary of NBILP, owns the remaining 33-1/3% Membership
Interest in Guardian.

         The PSA contains customary and other closing conditions that, if not
satisfied or waived, would result in the sale not occurring. These conditions
include, among others:

         o        continued accuracy of the representations and warranties
                  contained in the PSA;

         o        performance by each party of its obligations under the PSA;

         o        absence of any litigation, proceedings, law or order that
                  restrains, enjoins or otherwise prohibits the transaction or
                  makes the transaction unlawful; and

         o        all applicable time limitations under the Hart-Scott-Rodino
                  Antitrust Improvements Act of 1976, as amended, shall have
                  expired without the objection by the relevant governmental
                  authorities.

         Affiliates of WEC and WPS have transportation contracts with Guardian
for approximately 650 million cubic feet per day and 12.5 million cubic feet per
day, respectively. Additionally, affiliates of both WEC and WPS have signed
precedent agreements that support Guardian's proposed expansion project.

ITEM 7.01 REGULATION FD DISCLOSURE.

         On March 30, 2006, Northern Border Partners, L.P. issued a press
release regarding the purchase of 66 2/3% of the total outstanding Membership
Interests in Guardian and an update on Guardian's recently announced pipeline
expansion. A copy of the press release is furnished and attached as Exhibit 99.1
hereto and is incorporated herein by reference.

ITEM 9.01   FINANCIAL STATEMENTS AND EXHIBITS.

     (c)    Exhibits.

                 *2.1      Purchase and Sale Agreement by and among Wisconsin
                           Energy Corporation and WPS Investments, LLC and
                           Northern Border Intermediate Limited Partnership
                           dated as of March 30, 2006.

                  99.1     Northern Border Partners, L.P. press release dated
                           March 30, 2006.

* Northern Border Partners agrees to furnish supplementally to the Securities
and Exchange Commission, upon request, any schedules and exhibits to this
agreement, as set forth in the Table of Contents of the agreement, that have
not been filed herewith pursuant to Item 601(b)(2) of Regulation S-K.




                                   SIGNATURES

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.


                                NORTHERN BORDER PARTNERS, L.P.

Date:  March 30, 2006           By: /s/  Jerry L. Peters
                                    ------------------------------------
                                    Name:  Jerry L. Peters
                                    Title: Chief Financial and Accounting
                                             Officer







                                  EXHIBIT INDEX


Exhibit 2.1* --  Purchase and Sale Agreement by and among Wisconsin Energy
                 Corporation and WPS Investments, LLC and Northern Border
                 Intermediate Limited Partnership, dated as of March 30, 2006.


Exhibit 99.1 --  Northern Border Partners, L.P. press release dated
                 March 30, 2006.


* Northern Border Partners agrees to furnish supplementally to the Securities
and Exchange Commission, upon request, any schedules and exhibits to this
agreement, as set forth in the Table of Contents of the agreement, that have
not been filed herewith pursuant to Item 601(b)(2) of Regulation S-K.