The Illinois-Missouri League was an American minor league baseball league. It began operations in 1908, and continued through 1914.

1908
Hannibal left the league to join the American Association. The team in Havana folded. Newly formed teams in Beardstown, Illinois and Pekin, Illinois joined the league.

1909
The teams from Galesburg and Monmouth joined the Central Association. New teams in Clinton, Illinois and Lincoln, Illinois joined the league. Beardstown moved to Jacksonville, Illinois on July 21, and folded with Macomb on August 17.

1911
Taylorsville folded. A new team in Streator, Illinois formed and joined the league. The Champaign-Urbana Velvets changed their name to the Champaign Velvets. The team from Clinton moved to Kankakee, Illinois on May 16. Its record prior to the move was 2-5; thereafter, they went 54-51.

1913
New teams in LaSalle, Illinois and Ottawa, Illinois formed and joined the league. Kankakee and Lincoln both folded on July 3, before the season ended.
Ottawa and Streator left the league to join the Bi-State League. The teams in Champaign and LaSalle folded, and the league itself folded.