The 2005 Arizona Diamondbacks season was the franchise's 8th season in Major League Baseball and their 8th season at Bank One Ballpark in Phoenix, Arizona, as members of the National League West.

They looked to improve on their 51–111 record from 2004. They looked to contend in what was once again a weak National League West. They finished the season with a record of 77–85, good for second place in the division.

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

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

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

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

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

LEAGUE CHAMPIONS: South Bend