1920 St. Louis Cardinals season

The 1920 St. Louis Cardinals season was the team's 39th season in St. Louis, Missouri and the 29th season in the National League. The Cardinals went 75–79 during the season and finished fifth in the National League.

Regular season
Rogers Hornsby became a full-time second baseman. Hornsby won the first of his seven batting titles with a .370 batting average, and he also led the league in on-base percentage (.431), slugging percentage (.559), hits (218), total bases (329), doubles (44), and RBI (94). From a fielding perspective, Hornsby led the league in putouts, assists, and double plays.

Starters by position
''Note: Pos = Position; G = Games played; AB = At bats; H = Hits; Avg. = Batting average; HR = Home runs; RBI = Runs batted in''

Other batters
''Note: G = Games played; AB = At bats; H = Hits; Avg. = Batting average; HR = Home runs; RBI = Runs batted in''

Starting pitchers
Note: G = Games pitched; IP = Innings pitched; W = Wins; L = Losses; ERA = Earned run average; SO = Strikeouts

Other pitchers
Note: G = Games pitched; IP = Innings pitched; W = Wins; L = Losses; ERA = Earned run average; SO = Strikeouts

Relief pitchers
Note: G = Games pitched; W = Wins; L = Losses; SV = Saves; ERA = Earned run average; SO = Strikeouts

Farm system

 * Class B: Houston Buffaloes (Texas League; Jewel Ens, manager)
 * Class D: Fort Smith Twins (Western Association; Boss Schmidt, manager)