The 1990 United States Senate election in Montana took place on November 6, 1990. Incumbent United States Senator
Max Baucus, who was first elected in
1978 and was re-elected in
1984, ran for re-election. After winning the
Democratic primary, he moved on to the general election, where he was opposed by
Allen Kolstad, the
Lieutenant Governor of Montana and the
Republican nominee. Baucus ultimately ended up defeating Kolstad in a
landslide, winning his third term with ease.