The 1970 United States Senate election in Missouri took place on November 3, 1970. Incumbent Democratic U.S. Senator Stuart Symington was re-elected to a fourth term in office over Republican John Danforth (who would eventually succeed the retiring Symington in 1976).
Considered a safely Democratic state, Symington was seen as an overwhelming favorite, leading in one poll 54% to 28%. His campaign focused on his seniority, criticizing Richard Nixon, and generally ignoring his opponent, even refusing debates. That said, Danforth was seen as a possible contender for an upset. Near the campaigns end, Danforth was seen as closing the gap, providing a real threat to Symington. Symington won the race by just under 3 points.