The 1919 major league baseball season began on April 19, 1919. The regular season ended on September 29, with the Cincinnati Reds and Chicago White Sox as the regular season champions of the National League and American League, respectively. The postseason began with Game 1 of the 16th World Series, known for the infamous Black Sox Scandal, on October 1 and ended with Game 8 on October 9. The Cincinnati Reds defeated the Chicago White Sox, five games to three.

The 1919 World Series was the championship series in Major League Baseball (MLB) for the 1919 season. The 16th edition of the World Series, it matched the American League champion Chicago White Sox against the National League champion Cincinnati Reds. Although most World Series have been of the best-of-seven format, the 1919 World Series was a best-of-nine series. MLB decided to try the best-of-nine format partly to increase popularity of the sport and partly to generate more revenue.