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): JULY 15, 2003 TC PIPELINES, LP (Exact name of registrant as specified in its charter) DELAWARE 000-26091 52-2135448 (State or other jurisdiction (Commission (I.R.S. Employer of incorporation) File Number) Identification No.) 110 TURNPIKE ROAD, SUITE 203 01581 WESTBOROUGH, MASSACHUSETTS (Zip Code) (Address of principal executive offices) (508) 871-7046 (Registrant's telephone number, including area code)

ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS. (c) Exhibits. 99.1 Press Release issued by Northern Border Pipeline Company on July 15, 2003. ITEM 9. REGULATION FD DISCLOSURE On July 15, 2003, Northern Border Pipeline Company ("Northern Border Pipeline") issued a press release announcing that it has made further progress in recontracting and has now nearly sold out the long-haul firm capacity on its pipeline system. The additional capacity commitments are at the maximum transportation rates with terms of one to two years. In the same press release, Northern Border Pipeline also announced that Cargill, Incorporated ("Cargill") has finalized the assignment of all of the firm transportation capacity formerly held by Mirant Americas Energy Marketing, LP ("Mirant"), which is approximately 10% of Northern Border Pipeline's firm capacity and extends for terms into 2006 and 2008. Additionally, Cargill assumed the management services of Pan-Alberta Gas, Ltd. previously performed by Mirant. TC PipeLines, LP (the "Partnership") owns a 30% general partner interest in Northern Border Pipeline. A copy of the press release of Northern Border Pipeline is furnished as Exhibit 99.1. The information in Item 9 of this report is being furnished, not filed, pursuant to Regulation FD. Accordingly, the information in Item 9 of this report will not be incorporated by reference into any registration statement filed by the Partnership under the Securities Act of 1933, as amended, unless specifically identified therein as being incorporated therein by reference. The furnishing of the information in this report is not intended to, and does not, constitute a determination or admission by the Partnership, that the information in this report is material or complete, or that investors should consider this information before making an investment decision with respect to any security of the Partnership or any of its affiliates. -2-

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 thereunto duly authorized. TC PipeLines, LP By: TC PipeLines GP, Inc., its general partner Dated: July 15, 2003 By: /s/ Theresa Jang ---------------------------------------- Theresa Jang Controller -3-

EXHIBIT INDEX NUMBER EXHIBIT 99.1. Press Release issued by Northern Border Pipeline Company on July 15, 2003. -4-

EXHIBIT 99.1 [COMPANY LETTERHEAD] NEWS NORTHERN BORDER 13710 FNB Parkway PIPELINE COMPANY RELEASE Omaha, NE 68154-5200 Northern Plains Natural Gas Company, Operator For Further Information Contact: Media Contact: Martha Sumner-Kenney (402) 492-3401 Investor Contact: Ellen Konsdorf (402) 492-7500 NORTHERN BORDER PIPELINE COMPANY CAPACITY NEARLY SOLD OUT - --------------------------------------------------------- FOR IMMEDIATE RELEASE: TUESDAY, JULY 15, 2003 OMAHA - (NYSE: NBP; NASDAQ: TCLP) - Northern Border Pipeline Company announced today that it has made further progress in recontracting and has now nearly sold out the long-haul firm capacity on its pipeline system. The additional capacity commitments are at the maximum transportation rates with terms of one to two years. "We are very pleased to have essentially sold out this capacity," said Bill Cordes, chairman of the Northern Border Pipeline Management Committee. "We began the year with about 40% of our capacity expiring prior to November 1 of this year and, currently, less than 1% remains available. Recontracting this capacity at maximum rates reaffirms the value of holding space on our pipeline." Northern Border also announced that Cargill, Incorporated has finalized the assignment of all of the firm transportation capacity formerly held by Mirant Americas Energy Marketing, LP, which is approximately 10% of the pipeline's firm capacity and extends for terms into 2006 and 2008. Additionally, Cargill assumed the management services of Pan-Alberta Gas, Ltd. previously performed by Mirant. Northern Border Pipeline Company is a general partnership that owns and operates a 1,249-mile interstate pipeline that transported approximately 20 percent of all Canadian gas imported into the United States in 2002. Northern Border Partners, L.P. (NYSE:NBP) owns a 70 percent general partner interest in Northern Border Pipeline Company. The remaining 30 percent general partner interest is owned by TC PipeLines, LP (Nasdaq: TCLP). THIS PRESS RELEASE INCLUDES FORWARD-LOOKING STATEMENTS WITHIN THE MEANING OF SECTION 27A OF THE SECURITIES ACT OF 1933 AND SECTION 21E OF THE SECURITIES EXCHANGE ACT OF 1934. ALTHOUGH THE COMPANY BELIEVES THAT ITS EXPECTATIONS ARE BASED ON REASONABLE ASSUMPTIONS, IT CAN GIVE NO ASSURANCE THAT SUCH EXPECTATIONS WILL BE ACHIEVED. IMPORTANT FACTORS THAT COULD CAUSE ACTUAL RESULTS TO DIFFER MATERIALLY FROM THOSE IN THE FORWARD-LOOKING STATEMENTS INCLUDE NATURAL GAS DEVELOPMENT IN THE WESTERN CANADIAN SEDIMENTARY BASIN; COMPETITIVE CONDITIONS IN THE OVERALL NATURAL GAS MARKETS; PERFORMANCE OF CONTRACTUAL OBLIGATIONS BY THE SHIPPERS; OUR ABILITY TO MARKET PIPELINE CAPACITY ON FAVORABLE TERMS; AND THE PRICE OF NATURAL GAS.