Finale: 23.08.2004
| Medaille | Sportler | Nation |
| Gold | Jeremy Wariner | USA |
| Silber | Otis Harris | USA |
| Bronze | Derrick Brew | USA |
| Rang | Sportler | Nation | Sekunden |
| 1 | Jeremy Wariner | USA | 44,00 |
| 2 | Otis Harris | USA | 44,16 |
| 3 | Derrick Brew | USA | 44,42 |
| 4 | Alleyne Francique | Grenada | 44,66 |
| 5 | Brandon Simpson | Jamaika | 44,76 |
| 6 | Davian Clarke | Jamaika | 44,83 |
| 7 | Leslie Djhone | Frankreich | 44,94 |
| 8 | Michael Blackwood | Jamaika | 45,55 |