The men's 4 × 400 metres relay event at the 2003 Pan American Games was held on August 9.
Results edit
| Rank | Heat | Nation | Athletes | Time | Notes |
|---|---|---|---|---|---|
 |
2 |  Jamaica |
Michael Campbell, Sanjay Ayre, Lanceford Spence, Davian Clarke | 3:01.81 | |
 |
2 |  United States |
Mitch Potter, Ja'Warren Hooker, Adam Steele, James Davis | 3:01.87 | |
 |
2 |  Dominican Republic |
Arismendy Peguero, Carlos Santa, Julio Vidal, Félix Sánchez | 3:02.02 | NR |
| 4 | 2 |  Trinidad and Tobago |
Jacey Harper, Sherridan Kirk, Jamil James, Damion Barry | 3:05.28 | |
| 5 | 2 |  Bahamas |
Andrae Williams, Dennis Darling, Timothy Munnings, Nathaniel McKinney | 3:05.50 | |
| 6 | 2 |  Cuba |
Glauder Garzón, Sergio Hierrezuelo, Alianni Hechevarría, Yeimer López | 3:06.27 | |
| 7 | 2 |  Venezuela |
Jonathan Palma, Simoncito Silvera, Luis Luna, William Hernández | 3:06.52 | |
| 8 | 1 |  Grenada |
Bruce Swan, Sheldon Noel, Shane Charles, Alleyne Francique | 3:09.50 | |
| 9 | 1 |  Ecuador |
Cristian Gutiérrez, Andrés Gallegos, Luis Morán, Cristian Matute | 3:21.42 | |
| 1 |  Belize |
DNS |