Major League Baseball (MLB) is a professional baseball league, consisting of teams that play in the American League and the National League. The two leagues merged in 2000 into a single organization led by the Commissioner of Baseball, after 100 years as separate legal entities.
MLB constitutes one of the major professional sports leagues of the United States and Canada. It is composed of 30 teams — 29 in the United States and one in Canada. With the International Baseball Federation, MLB also manages the World Baseball Classic. MLB has the highest season attendance of any sports league in 2011.

Major League Baseball (MLB)