If both teams have scored the same number of runs at the end of a regular-length game, a tie is avoided by the addition of extra innings. As many innings as necessary are played until one team has the lead at the end of an inning. Thus, the home team always has a chance to respond if the visiting team scores in the top half of the inning; this gives the home team a small tactical advantage. In theory, a baseball game could go on forever; in practice, however, they eventually end. In Major League Baseball the longest game played was a 26-inning affair between the Brooklyn Robins and Boston Braves on May 1, 1920. The game ended in a 1-1 tie called on account of darkness.

In Major League Baseball, games end with tie scores only because conditions have made it impossible to continue play. A tie game does not count as an official game in the standings unless it is finished later or replayed; however, individual player statistics from tie games are counted. Inclement weather may also shorten games, but at least five innings must be played for the game to be considered official; four-and-a-half innings are enough if the home team is ahead. Previously, curfews and the absence of adequate lighting caused more ties and shortened games.

In Japanese baseball, if the score remains tied after nine innings, up to three extra innings may be played before the game is called a tie. Some youth or amateur leagues will end a game early if one team is ahead by ten or more runs, a practice known as the "mercy rule" or "slaughter rule". Rarely, a game can also be won or lost by forfeit.

Traditionally, there is a short break between the top half and the bottom half of the seventh inning, known as the seventh-inning stretch. During the "stretch," fans often sing the chorus of "Take Me Out to the Ball Game."