The 1940 United States House of Representatives election in New Mexico was held on Tuesday November 5, 1940 to elect the state's at-large representative to serve in the 77th United States Congress. Incumbent John J. Dempsey chose to run for the US Senate instead of seeking a fourth term in congress. Clinton Anderson won the open seat by 17.52% outperforming Franklin D. Roosevelt in the concurrent Presidential election by 4.21 percentage points.