The Major League Baseball postseason is an elimination tournament conducted after the regular season, by which MLB determines its World Series champion for a given year.
The MLB postseason format has evolved throughout its history, with the number of participating teams increasing from two (for its first six-plus decades) to the current 12, with a special format in having 16. The World Series was first played in 1903, when the champions of the established National League (NL) and the upstart American League (AL) met for a playoff series. From that time through 1968, the two leagues (which each had eight teams through 1960) each sent only its team with the best regular-season record to the World Series. In 1969, as each league had expanded to 12 teams, each league was divided into East and West divisions and another playoff round was created. This round became known as the League Championship Series (LCS), with the four division champions competing for a spot in the World Series every year. This format lasted until 1993.
In 1994, the again-expanded leagues were re-organized into three separate divisions, and another playoff round was established, called the Division Series (DS). In this format, for each league, the champions of the East, Central, and West divisions would be joined in the playoffs by a Wild Card team. The addition of the Wild Card allowed a team that was not a division winner but still had one of the top regular-season records to enter the postseason. In 1998, the system was slightly modified so that the division winners with better regular-season records would be rewarded with homefield advantage in the division series and LCS. In 2012, the structure was adjusted such that two teams from each league receive Wild Card berths and then play a single game against each other to determine who advances to the Division Series. It also eliminated the previous restriction that the wild card team could not play a team in its own division in the first round. In 2022, the current 12-team format was used, featuring a best-of-three Wild Card Series. However, in this format, the top two division winners in each league received an automatic berth to the Division Series, while the lowest-ranked division winner and three Wild Card teams would play in the Wild Card Series.
Three anomalies in the above-described system occurred. In 1904, the World Series did not take place because the National League champion did not wish to participate and the leagues had not yet agreed to require their champions to do so. In 1981, there was a Division Series due to a split season brought about by a midsummer player's strike. In 1994, the postseason did not take place due to a player's strike. And in 2020, after a shortened 60-game regular season due to the COVID-19 pandemic, a special best-of-three Wild Card Series was played; this involved the three division winners, three second-place teams from each division, and two Wild Card teams in each league.
Postseason appearances by franchise Postseason Appearances by Finish Franchise Years Lost Lost Lost Lost Won ATH Philadelphia Athletics 1903–1954 — — — , , , , , , Kansas City Athletics 1955–1967 — — — — — Oakland Athletics 1968–2024 , , , , , , , , , , , , , , , , Athletics (Sacramento) 2025–present — — — — — AZ Arizona Diamondbacks 1998–present — , , , ATL Boston Braves 1903–1952 — — — Milwaukee Braves 1953–1965 — — — Atlanta Braves 1966–present , , , , , , , , , , , , , , , , , , , , , BAL St. Louis Browns 1903–1953 — — — — Baltimore Orioles 1954–present , , , , , , , , , , BOS Boston Red Sox 1903–present , , , , , , , , , , , , , , , , , , , , , , CHC Chicago Cubs 1903–present , , , , , , , , , , , , , , , , , , CWS Chicago White Sox 1903–present , , , , , , CIN Cincinnati Reds 1903–present , , , , , , , , , , , , CLE Cleveland Guardians/Indians 1903–present , , , , , , , , , , , , , COL Colorado Rockies 1993–present , , — — DET Detroit Tigers 1903–present — , , , , , , , , , , , , , , HOU Houston Astros 1962–present , , , , , , , , , , , , , , KC Kansas City Royals 1969–present — , , , , , , LAA Los Angeles/California/Anaheim Angels 1961–present — , , , , , , , — LAD Brooklyn Dodgers 1903–1957 — — — , , , , , , , Los Angeles Dodgers 1958–present — , , , , , , , , , , , , , , , , , , , , , , , , , , MIA Miami/Florida Marlins 1993–present — — , MIL Seattle Pilots 1969 — — — — — Milwaukee Brewers 1970–present , , , , , , , —MIN Washington Senators 1903–1960 — — — , Minnesota Twins 1961–present , , , , , , , , , , NYM New York Mets 1962–present , — , , , , , , NYY New York Yankees 1903–present , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , PHI Philadelphia Phillies 1903–present , , , , , , , , , , , , , , PIT Pittsburgh Pirates 1903–present , , , , , , , , , , , , SD San Diego Padres 1969–present , , , , , — SEA Seattle Mariners 1977–present — , , , , — —SF New York Giants 1903–1957 — — — , , , , , , , , , , , , San Francisco Giants 1958–present — , , , , , , , , , STL St. Louis Cardinals 1903–present , , , , , , , , , , , , , , , , , , , , , , , , , , , TB Tampa Bay Rays/Devil Rays 1998–present , , , , , — , —TEX Washington Senators 1961–1971 — — — — — Texas Rangers 1972–present , , , , — , TOR Toronto Blue Jays 1977–present , , — , , , , , WSH Montreal Expos 1969–2004 — — — — Washington Nationals 2005–present — , , , — —
Franchise records by postseason round Updated through the 2025 postseason. Franchise Wild Card Game/ Series Division Series League Championship Series World Series Postseason Appearances Won Total Won Total Won Total Won Total Total Arizona Diamondbacks 2 2 3 7 2 3 1 2 7 Boston / Milwaukee / Atlanta Braves 2 4 8 19 6 13 4 10 31 St. Louis Browns / Baltimore Orioles 1 3 3 5 5 10 3 7 16 Boston Red Sox 1 3 8 14 6 12 9 13 27 Chicago Cubs 2 5 4 8 1 6 3 11 23 Chicago White Sox 1 2 1 4 1 3 3 5 12 Cincinnati Reds 0 3 1 3 5 8 5 9 17 Cleveland Indians / Guardians 1 4 6 12 3 6 2 6 19 Colorado Rockies 1 2 1 4 1 1 0 1 5 Detroit Tigers 2 2 4 7 3 7 4 11 18 Houston Astros 2 4 9 15 5 11 2 5 19 Kansas City Royals 2 2 2 4 4 8 2 4 10 Los Angeles / California / Anaheim Angels 0 0 3 7 1 6 1 1 10 Brooklyn / Los Angeles Dodgers 3 3 11 20 10 17 9 23 40 Florida / Miami Marlins 1 2 2 3 2 2 2 2 4 Seattle Pilots / Milwaukee Brewers 0 4 3 6 1 4 0 1 12 Washington Senators / Minnesota Twins 1 3 1 8 2 5 3 6 18 New York Mets 1 3 5 5 5 9 2 5 11 New York Yankees 5 7 15 25 12 19 27 41 61 Philadelphia / Kansas City / Oakland Athletics / Athletics 1 4 2 9 6 11 9 14 29 Philadelphia Phillies 2 3 5 10 6 11 2 8 19 Pittsburgh Pirates 1 3 0 1 2 9 5 7 17 San Diego Padres 4 5 2 7 2 3 0 2 10 Seattle Mariners 1 1 4 6 0 4 0 0 6 New York / San Francisco Giants 2 2 4 9 5 7 8 20 27 St. Louis Cardinals 1 4 11 14 7 14 11 19 32 Tampa Bay Devil Rays / Rays 3 5 2 7 2 2 0 2 10 Washington Senators / Texas Rangers 1 2 3 8 3 3 1 3 9 Toronto Blue Jays 1 4 3 3 3 8 2 3 11 Montreal Expos / Washington Nationals 1 1 2 6 1 2 1 1 6 Totals 46 92 128 256 112 224 121 242 536
See also List of Major League Baseball postseason series List of Major League Baseball franchise postseason droughts List of Major League Baseball franchise postseason streaks
External links MLB Postseason History at Baseball-Reference.com