1978 Seattle Mariners season

The 1978 Seattle Mariners season was the second in franchise history. The Mariners ended the season by finishing seventh in the American League West with a record of .350.

Offseason

 * March 27, 1978: Bob Galasso was released by the Mariners.
 * March 27, 1978: Mike Kekich was released by the Mariners.

Regular season

 * October 1, 1978: Kevin Pasley hit a home run in the last at bat of his career.

Notable transactions

 * June 6, 1978: Vance McHenry was drafted by the Mariners in the 11th round of the 1978 Major League Baseball Draft.

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