How Many Teams Are in MLB? 30 Teams Explained

By Sarah Miller · January 20, 2029

There are 30 teams in Major League Baseball (MLB), split evenly between the American League (AL) and National League (NL), each with 15 teams. These teams are further divided into three divisions—East, Central, and West—within each league. This structure supports balanced scheduling, competitive playoffs, and a consistent framework for the regular season and World Series contention.

Understanding MLB's Team Structure

Major League Baseball (MLB) is the premier professional baseball league in North America and consists of 30 franchises across the United States and Canada. The league has maintained this number since 1998, when the Arizona Diamondbacks and Tampa Bay Devil Rays (now Tampa Bay Rays) joined as expansion teams.

Key Components of MLB's Organization

Two Leagues: American League (AL) and National League (NL)
Six Divisions: Three per league (East, Central, West)
15 Teams per League: Ensures balanced interleague play and postseason eligibility
One Canadian Team: Toronto Blue Jays (the only non-U.S.-based team)

Historical Expansion of MLB Teams

MLB has evolved significantly since its founding in 1903. Originally consisting of just eight teams, the league expanded gradually to accommodate growing popularity, new markets, and television demands.

Milestones in MLB Expansion

1961: Los Angeles Angels and Washington Senators (expansion)
1962: Houston Colt .45s (later Astros) and New York Mets
1993: Colorado Rockies and Florida Marlins (now Miami Marlins)
1998: Arizona Diamondbacks and Tampa Bay Devil Rays

The last expansion brought the total to 30 teams, a number that has remained stable for over two decades despite ongoing discussions about potential future additions.

Current MLB Teams by Division

League	Division	Team	City/State	Founded	Joined MLB
American League	East	Boston Red Sox	Boston, MA	1901	1901
American League	East	New York Yankees	New York, NY	1901	1901
American League	East	Tampa Bay Rays	St. Petersburg, FL	1998	1998
American League	East	Toronto Blue Jays	Toronto, ON	1977	1977
American League	East	Baltimore Orioles	Baltimore, MD	1894	1901
American League	Central	Chicago White Sox	Chicago, IL	1901	1901
American League	Central	Cleveland Guardians	Cleveland, OH	1901	1901
American League	Central	Detroit Tigers	Detroit, MI	1894	1901
American League	Central	Kansas City Royals	Kansas City, MO	1969	1969
American League	Central	Minnesota Twins	Minneapolis, MN	1901	1901
American League	West	Houston Astros	Houston, TX	1962	1962
American League	West	Los Angeles Angels	Anaheim, CA	1961	1961
American League	West	Oakland Athletics	Oakland, CA	1901	1901
American League	West	Seattle Mariners	Seattle, WA	1977	1977
American League	West	Texas Rangers	Arlington, TX	1961	1961
National League	East	Atlanta Braves	Atlanta, GA	1871	1876
National League	East	Miami Marlins	Miami, FL	1993	1993
National League	East	New York Mets	New York, NY	1962	1962
National League	East	Philadelphia Phillies	Philadelphia, PA	1883	1883
National League	East	Washington Nationals	Washington, D.C.	1969	1969
National League	Central	Chicago Cubs	Chicago, IL	1870	1876
National League	Central	Cincinnati Reds	Cincinnati, OH	1869	1876
National League	Central	Milwaukee Brewers	Milwaukee, WI	1969	1970
National League	Central	Pittsburgh Pirates	Pittsburgh, PA	1882	1887
National League	Central	St. Louis Cardinals	St. Louis, MO	1882	1892
National League	West	Arizona Diamondbacks	Phoenix, AZ	1998	1998
National League	West	Colorado Rockies	Denver, CO	1993	1993
National League	West	Los Angeles Dodgers	Los Angeles, CA	1883	1890
National League	West	San Diego Padres	San Diego, CA	1969	1969
National League	West	San Francisco Giants	San Francisco, CA	1883	1883

Table data source:1, 2

The table shows the full distribution of all 30 MLB teams as of the 2025 season. Most teams have long histories, with several founding members still active today. The most recent additions—Arizona Diamondbacks (1998) and Tampa Bay Rays (1998)—highlight the late-20th-century expansion phase. Notably, the Milwaukee Brewers began in the AL before moving to the NL in 1998 to balance leagues after expansion.

How MLB Structure Impacts Competition

The 30-team format allows for regional rivalries, geographically efficient scheduling, and a structured playoff system. Each team plays 162 games in the regular season, with approximately 76 games against division rivals, enhancing competitive intensity within divisions.

Postseason Qualification Format

6 Teams per League: 3 division winners + 3 wild cards
Wild Card Games: Best-of-three series hosted by higher seed
League Championship Series: Best-of-seven to determine World Series participants

This structure rewards division titles while giving high-performing non-division winners a path to the World Series.

Frequently Asked Questions About MLB Teams

How many baseball teams are in MLB?

There are 30 teams in Major League Baseball (MLB), with 15 in the American League and 15 in the National League.

Why does MLB have 30 teams?

MLB expanded to 30 teams in 1998 with the addition of the Arizona Diamondbacks and Tampa Bay Rays to promote national coverage, regional representation, and financial growth through broader media rights and fan bases.

Are there any plans to expand MLB beyond 30 teams?

As of 2025, there are no official plans for expansion, though cities like Nashville, Montreal, and Portland have been discussed as potential markets. Any expansion would require approval from team owners and likely involve adding two teams to maintain league balance.