2004 Nippon Professional Baseball season

The 2004 Nippon Professional Baseball season ended with the Seibu Lions defeating the Chunichi Dragons in the 2004 Japan Series. This season also saw the first and only players strike in Japanese professional baseball history. Players went on strike for two days in September because of the potential mergers and realignment.

Central League

 * Season Format
 * Regular Season
 * Regular Season 1st place is the champion

Pacific League

 * Season Format
 * Regular Season
 * Playoff 1st Stage: Regular Season 2nd place vs. Regular Season 3rd place – Best of 3
 * Playoff 2nd Stage: Regular Season 1st place vs. Playoff 1st Stage winner – Best of 5
 * Playoff 2nd Stage winner is the champion

Japan Series

 * Central League champion vs. Pacific League champion – Best of 7

Standings
Note:Two games for each team are cancelled due to players' strike

Playoff 1st Stage
Seibu Lions (2) vs. Hokkaido Nippon-Ham Fighters (1)

Playoff 2nd Stage
Fukuoka Daiei Hawks (2) vs. Seibu Lions (3)

Japan Series
Chunichi Dragons (3) vs. Seibu Lions (4)