Harkin: 40–50% 50–60% 60–70%
Jepsen: 40–50% 50–60% 60–70% 70–80%
The 1984 United States Senate election in Iowa was held on November 6, 1984. Incumbent Republican U.S. Senator Roger Jepsen ran for re-election to a second term in office. Jepsen was opposed by U.S. Congressman Tom Harkin, from Iowa's 5th congressional district, who won the Democratic primary uncontested. The general election was full of mudslinging and personal attacks, including the embellishment by both candidates of their military records; Harkin attacked Jepsen for failing to keep his promise to not sell AWACS aircraft to Saudi Arabia. Ultimately, Harkin defeated Jepsen by a wide margin, winning the first of five terms in the Senate.
- Roger Jepsen, incumbent U.S. Senator
|Republican||Roger Jepsen (incumbent)||113,996||99.87%|
|Republican||Roger Jepsen (incumbent)||564,381||43.66%||-7.47%|
|Independent||Garry De Young||11,014||0.85%|
|Democratic gain from Republican||Swing|
- Clerk of the United States House of Representatives (1985). "Statistics of the Presidential and Congressional Election of November 6, 1984" (PDF). U.S. Government Printing Office.