The St. Louis Cardinals 1981 season was the team's 100th season in St. Louis, Missouri and the 90th season in the National League. 1981 was a season of two significant anomalies: A change in the playoff format, which created the first-ever NLDS with a qualification variant that existed only for that season, and the players' strike, which truncated the regular season. Despite finishing 59-43, good for the best overall record in the National League East, the strike set up the scenario where the Cardinals actually missed the playoffs. The regular season was split into halves to tally teams' records separately in each half of the season, and because the Cardinals finished in second place in each half, they did not qualify for the 1981 playoffs. Major League Baseball reverted to the previous playoff format the following season, and the Cardinals qualified for that postseason. First baseman Keith Hernandez won a Gold Glove this year.

Offseason

Regular season

Season standings

Record vs. opponents

Opening Day starters

Notable transactions

Roster

Player stats

Batting

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''

Pitching

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