| Election Name: | 1974 United States Senate election in Colorado |
| Country: | Colorado |
| Type: | Presidential |
| Ongoing: | no |
| Previous Election: | 1968 United States Senate election in Colorado |
| Previous Year: | 1968 |
| Next Election: | 1980 United States Senate election in Colorado |
| Next Year: | 1980 |
| Election Date: | November 5, 1974 |
| Image1: | File:Gary hart.jpg |
| Nominee1: | Gary Hart |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 471,691 |
| Percentage1: | 57.23% |
| Nominee2: | Peter Dominick |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 325,508 |
| Percentage2: | 39.50% |
| Map Size: | 250px |
| U.S. Senator | |
| Before Election: | Peter Dominick |
| Before Party: | Republican Party (United States) |
| After Election: | Gary Hart |
| After Party: | Democratic Party (United States) |
The 1974 United States Senate election in Colorado took place on November 5, 1974. Incumbent Republican U.S. Senator Peter Dominick ran for re-election to a third term in office, but was defeated by Democrat Gary Hart.As of, this is the last time that an incumbent Senator from Colorado lost re-election for this seat, and the last time that El Paso County voted for the Democratic candidate in a Senate election.