The 1990 United States Senate election in South Dakota was held on November 6, 1990. Incumbent Republican U.S. Senator Larry Pressler ran for re-election to a third term, beating Democratic nominee Theodore 'Ted' Muenster by 19,000 votes. This was the last time until 2014 that a Republican would be elected to South Dakota's Class 2 Senate seat.
1990 United States Senate election in South Dakota