Carsharing provides members access to a fleet of autos for short-term use throughout the day, reducing the need for one or more personal vehicles. Over ten years ago, carsharing operators began to appear in North America. Since 1994, a total of 40 programs have been deployed–28 are operating in 36 urban areas and 12 are now defunct. Another four are planned to launch in the next year. This paper examines carsharing growth potential in North America, based on a survey of 26 existing organizations conducted from April to July 2005. Since the mid-1990s, the number of members and vehicles supported by carsharing in the U.S. and Canada continues to grow, despite program closures. The three largest providers in the U.S. and Canada both support 94% of the total carsharing membership. Growth potential in major metropolitan regions is estimated at 10% of individuals over the age of 21 in North America. While carsharing continues to gain popularity and market share, the authors conclude that increased carsharing education, impact evaluation, and supportive policy approaches, including mainstreaming carsharing as a transportation strategy.