Underwriters Exercise Over-Allotment Option on TransCanada Common Shares

CALGARY, Alberta – June 25, 2009 –TransCanada Corporation (TSX, NYSE: TRP) (TransCanada) today announced that the underwriters of its recent common share offering have exercised their over-allotment option to purchase an additional 7,620,000 common shares at a price of $31.50 per common share. Closing of the exercise of the over-allotment option is expected to occur on June 30, 2009.

The gross proceeds from the over-allotment option total approximately $240 million. Gross proceeds from the common share offering and the over-allotment option total approximately $1.84 billion. The net proceeds will be used by TransCanada to partially fund capital projects of the Corporation, including the acquisition of an additional interest in the Keystone Pipeline System, for general corporate purposes and to repay short-term indebtedness.

With more than 50 years’ experience, TransCanada is a leader in the responsible development and reliable operation of North American energy infrastructure including natural gas pipelines, power generation, gas storage facilities, and projects related to oil pipelines. TransCanada’s network of wholly owned pipelines extends more than 59,000 kilometres (36,500 miles), tapping into virtually all major gas supply basins in North America. TransCanada is one of the continent’s largest providers of gas storage and related services with approximately 370 billion cubic feet of storage capacity. A growing independent power producer, TransCanada owns, or has interests in, over 10,900 megawatts of power generation in Canada and the United States. TransCanada’s common shares trade on the Toronto and New York stock exchanges under the symbol TRP.

Note: All financial figures are in Canadian dollars unless noted otherwise.

FORWARD-LOOKING INFORMATION

This news release may contain certain information that is forward looking and is subject to important risks and uncertainties. The words "anticipate", "expect", "believe", "may", "should", "estimate", "project", "outlook", "forecast" or other similar words are used to identify such forward-looking information. Forward-looking statements in this document are intended to provide TransCanada security holders and potential investors with information regarding TransCanada and its subsidiaries, including management’s assessment of TransCanada’s and its subsidiaries’ future financial and operations plans and outlook.  Forward-looking statements in this document may include, among others, statements regarding the anticipated business prospects and financial performance of TransCanada and its subsidiaries, expectations or projections about the future, and strategies and goals for growth and expansion.  All forward-looking statements reflect TransCanada’s beliefs and assumptions based on information available at the time the statements were made. Actual results or events may differ from those predicted in these forward-looking statements. Factors that could cause actual results or events to differ materially from current expectations include, among others, the ability of TransCanada to successfully implement its strategic initiatives and whether such strategic initiatives will yield the expected benefits, the operating performance of TransCanada’s pipeline and energy assets, the availability and price of energy commodities, regulatory processes and decisions, changes in environmental and other laws and regulations, competitive factors in the pipeline and energy sectors, construction and completion of capital projects, labour, equipment and material costs, access to capital markets, interest and currency exchange rates, technological developments and the current economic conditions in North America. By its nature, forward‑looking information is subject to various risks and uncertainties, which could cause TransCanada's actual results and experience to differ materially from the anticipated results or expectations expressed. Additional information on these and other factors is available in the reports filed by TransCanada with Canadian securities regulators and with the U.S. Securities and Exchange Commission (SEC). Readers are cautioned to not place undue reliance on this forward‑looking information, which is given as of the date it is expressed in this news release or otherwise, and to not use future-oriented information or financial outlooks for anything other than their intended purpose. TransCanada undertakes no obligation to update publicly or revise any forward‑looking information, whether as a result of new information, future events or otherwise, except as required by law.

- 30 -

For further information, please contact:

Media Inquiries:
Cecily Dobson
(403) 920-7859
(800) 608-7859

Investor & Analyst Inquiries:
David Moneta / Myles Dougan / Terry Hook
(403) 920-7911
(800) 361-6522