List of Major League Baseball franchise postseason streaks

This is a list of Major League Baseball (MLB) franchise postseason and World Series streaks. The list includes only the modern World Series between the American League (AL) and the National League (NL), not the various 19th-century championship series.

The most successful postseason team in MLB history is the New York Yankees, who have achieved three of the four instances of a franchise winning more than two World Series championships in a row (one streak each of durations 3, 4, and 5 seasons) and five of the six instances of a franchise winning the league pennant (i.e., an appearance in the World Series) more than three times in a row (three streaks of 4 seasons and two streaks of 5 seasons). The only other franchises to achieve these milestones are the Oakland Athletics, who won three consecutive championships from 1972 to 1974, and the New York Giants, who won four consecutive pennants from 1921 to 1924. The Yankees also achieved a remarkable run of appearing in 15 of the 18 World Series from 1947 to 1964.

Beginning in 1969, MLB split into four divisions, and the winners of each competed in the League Championship Series, with the winners advancing to the World Series. When a multi-tier playoff system was implemented in 1995, the LCS remained the series that determined the pennant-winner. The longest streak of consecutive LCS appearances belongs to the Atlanta Braves with 8 in a row from 1991 to 1999 (not counting 1994, when there were no playoffs), while the second-longest belongs to the Oakland Athletics with 5 in a row from 1971 to 1975.

Further expansion of the postseason began in 1995, with eight teams entering the playoffs each year (further expanded to ten teams in 2012). In this era, the Braves entered the postseason 14 consecutive years from 1991 to 2005 (again not counting 1994), while the Yankees had a streak of 13 appearances from 1995 to 2007. However, all other postseason appearance streaks of 5 years or more predate the expanded-postseason era and are mentioned above, except for 5-year runs by the Cleveland Indians (1995–1999), the Philadelphia Phillies (2007–2011), and the St. Louis Cardinals (2011–2015).

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