The 1938 United States Senate elections in South Dakota took place on November 8, 1938. Incumbent Republican Senator Peter Norbeck died in office on December 20, 1936. Herbert E. Hitchcock was appointed by Governor Tom Berry as Norbeck's replacement. Two elections for the same Senate seat were held on the same day; one as a special election to fill the remainder of Norbeck's six-year term, and another to select a Senator to serve the next six-year term.