TC PipeLines, LP Announces First Quarter Cash Distribution

  TC PipeLines, LP (NASDAQ: TCLP) (the Partnership) today announced the board of directors of TC PipeLines GP, Inc., its general partner, has declared the Partnership's first quarter 2010 cash distribution in the amount of $0.73 per common unit. This cash distribution is equivalent to the fourth quarter 2009 distribution and represents a 3.5 per cent increase from the first quarter 2009 distribution of $0.705 per common unit.

This cash distribution is the 44th consecutive quarterly distribution paid by the Partnership. This distribution is payable on May 14, 2010 to unitholders of record as of April 30, 2010.

TC PipeLines, LP has interests in approximately 3,700 miles of federally regulated U.S. interstate natural gas pipelines, including Great Lakes Gas Transmission Limited Partnership (46.45 per cent ownership), Northern Border Pipeline Company (50 per cent ownership), North Baja Pipeline, LLC (100 per cent ownership) and Tuscarora Gas Transmission Company (100 per cent ownership). Great Lakes is a 2,115-mile natural gas pipeline system serving markets in Minnesota, Wisconsin, Michigan and eastern Canada. The 1,249-mile Northern Border Pipeline transports natural gas from the Montana-Saskatchewan border to markets in the midwestern United States. North Baja is an 80-mile natural gas pipeline system that transports natural gas between southwestern Arizona and a point on the California/Mexico border where it connects with a natural gas pipeline system in Mexico. Tuscarora is a 240-mile pipeline system that transports natural gas from Oregon, where it interconnects TransCanada's Gas Transmission Northwest System, to markets in Oregon, California and Nevada. TC PipeLines, LP is managed by its general partner, TC PipeLines GP, Inc., an indirect wholly owned subsidiary of TransCanada Corporation. TC PipeLines GP, Inc. also holds common units of TC PipeLines, LP. Common units of TC PipeLines, LP are quoted on the NASDAQ Stock Market and trade under the symbol "TCLP." For more information about TC PipeLines, LP, visit the Partnership's website at www.tcpipelineslp.com.

Contacts: TC PipeLines, LP Media Inquiries Cecily Dobson/Terry Cunha 403.920.7859 or 800.608.7859 TC PipeLines, LP Unitholder and Analyst Inquiries Terry Hook 877.290.2772 [e-mail] www.tcpipelineslp.com