Claim: Major League Soccer playoffs involves 12 teams competing against each other.

Major League Soccer -LRB- MLS -RRB- is a men 's professional soccer league , sanctioned by U.S. Soccer , that represents the sport 's highest level in both the United States and Canada . MLS constitutes one of the major professional sports leagues of the United States and Canada . The league comprises 22 teams -- 19 in the U.S. and 3 in Canada . The MLS regular season runs from March to October , with each team playing 34 games ; the team with the best record is awarded the Supporters ' Shield . The postseason includes twelve teams competing in the MLS Cup Playoffs through November and December , culminating in the championship game , the MLS Cup . MLS teams also play in other domestic competitions against teams from other divisions in the U.S. Open Cup and in the Canadian Championship . MLS teams also compete against continental rivals in the CONCACAF Champions League .   Major League Soccer was founded in 1993 as part of the United States ' successful bid to host the 1994 FIFA World Cup . The first season took place in 1996 with ten teams . MLS experienced financial and operational struggles in its first few years : The league lost millions of dollars , teams played in mostly empty American football stadiums , and two teams folded in 2002 . Since then , MLS has expanded to 22 teams , owners built soccer-specific stadiums , average MLS attendance exceeds that of the National Hockey League -LRB- NHL -RRB- and National Basketball Association -LRB- NBA -RRB- , MLS secured national TV contracts , and the league is now profitable .   Instead of operating as an association of independently owned teams , MLS is a single entity in which each team is owned and controlled by the league 's investors . The investor-operators control their teams as owners control teams in other leagues , and are commonly -LRB- but inaccurately -RRB- referred to as the team 's owners . The league has a fixed membership , like most sports leagues in the United States and Canada , which makes it one of the world 's few soccer leagues that does not use promotion and relegation , a practice that is uncommon in the two countries . MLS headquarters is located in New York City .