The 1904 Major League Baseball season was contested from April 14 to October 10, 1904. The Boston Americans and New York Giants finished atop the standings for the American League and National League, respectively. There was no postseason, as the Giants declined to meet the Americans in a World Series.

The St. Louis Browns and Detroit Tigers played 11 consecutive games against each other in September—the first six in Detroit and the final five in St. Louis^[1]—the most games played consecutively between two teams in major league history.^[2]

The 1904 schedule consisted of 154 games (an increase from 140 from the previous season) for all teams in the American League and National League, each of which had eight teams. Each team was scheduled to play 22 games against the other seven teams of their respective league. This format was an adjustment to the 140-game, 20-games-each format that had been in place from the 1901 season. This format would last until 1919.

Opening Day took place on April 14 with all but the Pittsburgh Pirates and St. Louis Cardinals playing. The National League and American League would see their final day of the regular season on October 9 & 10, respectively.

No postseason was held this year.

• May 5 – Cy Young
• August 17 – Jesse Tannehill

• May 30 – Frank Chance of the Chicago Cubs is hit by a pitch five times in a double header.^[19][20]