| Election Name: | 2004 United States Senate election in Hawaii |
| Country: | Hawaii |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1998 United States Senate election in Hawaii |
| Previous Year: | 1998 |
| Next Election: | 2010 United States Senate election in Hawaii |
| Next Year: | 2010 |
| Election Date: | November 2, 2004 |
| Image1: | Daniel Inouye official portrait.jpg |
| Nominee1: | Daniel Inouye |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 313,629 |
| Percentage1: | 75.51% |
| Nominee2: | Campbell Cavasso |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 87,172 |
| Percentage2: | 20.99% |
| Map Size: | 300px |
| U.S. Senator | |
| Before Election: | Daniel Inouye |
| Before Party: | Democratic Party (United States) |
| After Election: | Daniel Inouye |
| After Party: | Democratic Party (United States) |
The 2004 United States Senate election in Hawaii took place on November 2, 2004 alongside other elections to the United States Senate in other states as well as elections to the United States House of Representatives and various state and local elections. Incumbent Democrat U.S. Senator Daniel Inouye won re-election to an eighth term in yet another landslide with over 75% of the vote, despite the state's relatively close single-digit margin of victory for John Kerry in the concurrent presidential election.
Inouye won every county with at least 70% of the vote. His best performance was in Kauai County, where he won with about 80%; also was Cavasso's weakest performance, getting just 16.5% of the vote there.