MLB Logo – The Major League Baseball or Major League Baseball (Major League Baseball or MLB in English) are the leagues of baseball higher-level professional in the world. This term refers mainly to the entity that operates the two most important leagues in the United States (and a team of Canada), the National League and American League, by means of a joint organizational structure that has existed since 1903. The American League is different from the NL used the rule of the designated hitter.

In games of the NL pitcher is usually the ninth batter. During games the World Series, the use of this distinction depends on where the game is played. For example, if the game is played in Yankee Stadium, the American League rules take effect because the team that plays in the stadium is in this league. In the All-Star Game will be used whenever the designated hitter, the difference lies in the manner of electing the designated hitter. Since 2000 the two leagues have been legally separated and then they are two separate entities operating from the address of the office of commissioner of the MLB.

In total there are 30 teams in two leagues: 16 in the National League and 14 in the American League . Each consists of three divisions, grouped by geographic location and named as “East”, “Central” and “West”. A season usually lasts from April to September. Each team plays 162 regular season games. This duration was established in 1961. From 1898 to 1960, 154 games were played. The games were played between teams from the same league. In 1997, the leadership of Major League Baseball introduced interleague play.