The Negro World Series was a post-season baseball tournament that was held from 1924 to 1927 and from 1942 to 1948 between the champions of the Negro leagues, matching the mid-western winners against their east-coast counterparts. The series was also known as the Colored World Series, especially during the 1920s, and as the Negro League World Series, in more recent books, though contemporary black newspapers usually called it simply, the "World Series", without any modification.
After the organization of first Negro National League (NNL) in 1920 and of the Eastern Colored League (ECL) in 1923, many Negro league fans hoped that the two leagues would compete in a post-season championship similar to the World Series held by the white leagues. On September 2, 1924, Rube Foster, president of the NNL announced that Judge Kenesaw Mountain Landis, Commissioner of Baseball for the white major leagues, had been asked to arbitrate the differences between the NNL and the ECL and establish an agreement similar to the one used by the American and National Leagues. The proposed agreement required the two leagues to respect each other's contracts, made allowances for players who had jumped contracts to stay with their current teams, and for a post-season championship between the leagues. The first championship was between the Kansas City Monarchs of the NNL and the Hilldale Club of the ECL.
In 1928, the ECL folded, with their teams returning to independent play, and the series entered a 15-year hiatus. The first NNL also folded after the 1931 season.
A second Negro National League was organized in 1933, though this league played predominantly in the East. The Negro American League was organized in 1937 in the West. In 1942, the two leagues agreed to resume playing a championship series between the two leagues; the first series was played between the Kansas City Monarchs of the NAL and the Homestead Grays of the NNL.