1990 United States Senate election in South Dakota

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.

Democratic

 * Theodore 'Ted' Muenster, Former Dean at University of South Dakota, Former Chief of Staff for Governor Kneip

Republican

 * Larry Pressler, incumbent U.S. Senator