Major League Baseball (MLB) is the main professional baseball organization and the oldest among four major American professional sports leagues (with the others being National Football League, National Basketball League and National Hockey League).

Thanks to the quality level of its player, MLB is widely regarded as the main and most famous baseball league worldwide.

Today, Major League Baseball is composed of thirty teams: twenty-nine of them are based in the United States and only one is based in Canada.

The thirty MLB teams are split into two leagues: 15 teams are part of the National League (NL), founded in 1876 and the oldest professional sports league worldwide, while the remaining 15 are part of the American League (AL). Each league is subsequently divided into three divisions each: East, Central and West

Each Major League Baseball team plays a 162-game regular season, which typically starts the first Sunday of April and ends the first Sunday of October.

A total of ten teams enter the MLB postseason playoffs: the six division champions, those teams that earned the best regular season overall win-loss record for their divisions, and four wild-card teams, the four non-division champions teams with the best regular season record (two for the National League and two for the American League).

Four postseason rounds of series of games are played in order to determine the MLB season champion:

• Wild Card Game between the two wild-card teams in each league.
• American and National League Division Series, a best-of-five-games series
• American and National League Championship Series, a best-of-seven-games series played between the winning teams of the previous round.
• World Series, a best-of-seven-games final series played between the two league champions that dates back to 1903. 2016 Major League Baseball World Series are played between Chicago Cubs and Cleveland Indians.

MLB National League Teams

• East division: Atlanta Braves, Miami Marlins, New York Mets, Philadelphia Phillies, Washington Nationals.
• Central division: Chicago Cubs, Cincinnati Reds, Milwaukee Brewers, Pittsburgh Pirates, St. Louis Cardinals
• West division: Arizona Diamondbacks, Colorado Rockies, Los Angeles Dodgers, San Diego Padres, San Francisco Giants

MLB American League

• East Division: Baltimore Orioles, Boston Red Sox, New York Yankees, Tampa Bay Rays, Toronto Blue Jays
• Central Division: Chicago White Sox, Cleveland Indians, Detroit Tigers, Kansas City Royals, Minnesota Twins
• West Division: Houston Astros, Los Angeles Angels of Anaheim, Oakland Athletics, Seattle Mariners, Texas Rangers.