1906 Major League Baseball season

The regular season ended on October 7, with the Chicago Cubs and Chicago White Sox as regular season champions of the National League and American League, respectively.

The White Sox defeated the Cubs, four games to two, capturing their first championship in franchise history.

National League Opening Day took place on April 12 with all teams playing, while American League Opening Day did not take place until April 14 with four teams playing.

Their .763 winning percentage remains the highest in the modern (two-league) era.

The Cubs' pitching staff consisted of Ed Reulbach, Carl Lundgren, Mordecai Brown and left-hander Jack Pfiester.