How many Major League Baseball teams are there?

In 1903, the year of the first World Series, there were 16 teams in Major League Baseball — eight in the American League and eight in the National League. Today, there are 30 teams in MLB. Each league has 15 teams.

When did MLB first expand in the 20th century?

From the beginning of the 20th century to the 1960s, despite several franchises relocating, Major League Baseball stayed at 16 teams. That changed in 1961, when the California Angels and Washington Senators (who would move to Texas and become the Rangers) entered the American League.

In 1962, the National League added the New York Mets and Houston Colt 45s (now Astros). In 1969, four more franchises were added, upping the number of MLB teams to 24. The San Diego Padres and Montreal Expos (now Washington Nationals) joined the NL that year; the Seattle Pilots (now Milwaukee Brewers) and Kansas City Royals joined the AL. 

When did MLB last expand?

In 1977, the Seattle Mariners and Toronto Blue Jays were added to the American League. MLB did not expand again until 1993, when the National League welcomed the Florida Marlins (now Miami Marlins) and Colorado Rockies. In 1998, each league added a franchise — the Tampa Bay Devil Rays (now Tampa Bay Rays) in the American League and Arizona Diamondbacks in the National League. The addition of those teams brought MLB to its present number of 30 teams.

AMERICAN LEAGUE

East 

Baltimore Orioles

Boston Red Sox

New York Yankees

Tampa Bay Rays

Toronto Blue Jays

Central

Chicago White Sox

Cleveland Indians

Detroit Tigers

Kansas City Royals

Minnesota Twins

West  

Houston Astros

Los Angeles Angels

Oakland Athletics

Seattle Mariners

Texas Rangers

NATIONAL LEAGUE

East 

Atlanta Braves

Miami Marlins

New York Mets

Philadelphia Phillies

Washington Nationals

Central

Chicago Cubs

Cincinnati Reds

Milwaukee Brewers

Pittsburgh Pirates

St. Louis Cardinals

West

Arizona Diamondbacks

Colorado Rockies

Los Angeles Dodgers

San Diego Padres

San Francisco Giants