The 1980 United States Senate election in Iowa was held on November 4, 1980. Incumbent Democratic United States Senator John Culver ran for reelection to a second term, but lost to Republican nominee Chuck Grassley, the United States Congressman from Iowa's 3rd congressional district.
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County Results | |||||||||||||||||
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| Party | Candidate | Votes | % | |
|---|---|---|---|---|
| Democratic | John Culver (incumbent) | 95,656 | 99.95% | |
| Democratic | Write-ins | 52 | 0.05% | |
| Total votes | 95,708 | 100.00% | ||
| Party | Candidate | Votes | % | |
|---|---|---|---|---|
| Republican | Chuck Grassley | 170,120 | 65.54% | |
| Republican | Tom Stoner | 89,409 | 34.45% | |
| Republican | Write-ins | 34 | 0.01% | |
| Total votes | 259,563 | 100.00% | ||
| Party | Candidate | Votes | % | ±% | |
|---|---|---|---|---|---|
| Republican | Chuck Grassley | 683,014 | 53.49% | +4.21% | |
| Democratic | John Culver (incumbent) | 581,545 | 45.54% | -4.48% | |
| Independent | Garry De Young | 5,858 | 0.46% | ||
| Libertarian | Robert V. Hengerer | 4,233 | 0.33% | ||
| Independent | John Ingram Henderson | 2,336 | 0.18% | ||
| Majority | 101,469 | 7.95% | +7.20% | ||
| Turnout | 1,772,983 | ||||
| Republican gain from Democratic | Swing | ||||
