A complete game is recorded when a starting pitcher finishes a game without leaving for a relief pitcher. While a complete game usually lasts nine innings, its length can differ under the following conditions:
- If the pitcher is playing for the visiting team, and it is trailing after taking its turn at bat in the ninth inning, the pitcher is credited with an eight-inning complete game loss. The pitcher is still credited with a complete game if he was removed for a pinch hitter in the top of the ninth inning;
- If the pitcher allows the home team to score the winning run in the bottom of the ninth inning, he is credited with a complete game of either 8 inning, 8.1 innings or 8.2 innings, depending on the number of outs recorded when the game ended;
- If a game is called early due to weather or darkness, or any other factor, the pitcher is credited with a complete game of however many official innings have been played;
- If a game goes into extra innings, the pitcher's complete game can be as long as the game lasts; a number of complete games of 15 innings or more have been recorded in Major League Baseball.
In 1984, Milt Wilcox became the first pitcher to spend an entire season in a starting rotation without recording a complete game. While seasons of 20 or more complete games were common until then, it is now very rare for a pitcher to record more than 10 complete games in a season, due to the increased use of specialized relief pitchers, and increasing reliance on pitch counts to dictate when a pitcher should be removed from the game.
|All Time Leaders|
|Season (since 1901)||Jack Chesbro||48||1904|
|NPB Career||Masaichi Kaneda||365|
|AAGPBL Season||Helen Fox||40|