Baseball is especially popular in North America, parts of Central- and South America, and parts of East Asia.
- Major League Baseball (MLB) is the highest level of professional baseball in the United States and Canada. MLB consists of two parts: National League (NL) and American League (AL). NL is for United States teams only, while AL features teams from both the U.S. and Canada. (more below)
- Mexico has two professional baseball leagues, the Mexican League (Liga Mexicana de Béisbol) and the Mexican Pacific League (Liga Mexicana del Pacífico). The Mexican League is the only Minor League Baseball (MiLB) sanctioned triple-A league outside the United States.
- The main professional baseball league of Puerto Rico is the Puerto Rico Baseball League, formerly known as Liga de Béisbol Profesional de Puerto Rico.
- In Central and South America, professional baseball leagues exist in Colombia, the Dominican Republic, Nicaragua, and Venezuela.
- Colombian Professional Baseball League
- Dominican Summer League (Official Minor League Affiliate)- Dominican Winter Baseball League
- Nicaraguan Professional Baseball League
- Venezuelan Summer League (Official Minor League Affiliate)
- Venezuelan Professional Baseball League
- In Asia, professional baseball leagues exist in China, Taiwan, South Korea, and Japan.
- China Baseball League- Chinese
- Professional Baseball League (Taiwan)
- Korea Professional Baseball
- Korea Baseball Futures League
- Nippon Professional Baseball (Japan)
- Baseball Challenge League (Japan)
- Kansai Independent Baseball League (Japan)
– Shikoku-Kyūshū Island League (Japan)
In the year 2000, the National League and the American League merged into a single Major League Baseball (MLB) organization headed by the Commissioner of Baseball. The commissioner is chosen by a vote of the owners of the teams.
MLB is comprised of 30 teams of which only one is Canadian, the rest are United States teams. 16 teams play in the National League and 14 teams play in the American League.
The National League and the American League are both subdivided into three divisions each.
- National League East
- National League Central
- National League West
- American League East
- American League Central
- American League West
The Major League Baseball season consists of 162 games. The seasons starts with Opening Day in early April and runs for 26 weeks. The last game of the MLB season is normally played on the last Sunday of September or first Sunday of October. During this regular season, teams generally play games six days a week and only get Monday or Thursday to rest. The aim for each team is to get to one of the four playoff berths available in their league. A team can get to playoff either by winning their division or by capturing a wild card spot.
During one weekend in mid-May as well as during the last two thirds of June, the MLB teams engage in interleague play.
In early July, an MLB All-Star Game takes place. In the All-Star game, a team consisting of National League players compete against a team consisting of American League players.