1940 United States Senate special election in Illinois

The 1940 United States Senate special election in Illinois took place on November 5, 1940. The election was triggered by the vacancy left by the death in office of Democrat J. Hamilton Lewis. After Lewis' death, James M. Slattery was appointed to fill the seat in the interim period until the individual elected in the special election would be sworn-in. Slattery was the Democratic Party's nominee in the special election. He was defeated by Republican nominee Charles W. Brooks. Brooks' father-in-law, Senator John Thomas of Idaho also won a special election that same day and the two would serve in the Senate together until Thomas' death in 1945.

Election information
The primaries and general election coincided with those for other federal elections (president and House) and those for state elections.

Primaries were held April 9, 1940.

Candidates

 * Benjamin S. Adamowski, State Representative from Chicago
 * James M. Slattery, interim Senator and former chairman of the Illinois Commerce Commission

Candidates

 * C. Wayland Brooks, nominee for Governor in 1936
 * Ralph E. Church, U.S. Representative from Evanston