| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 141 | Daniel Caines |  GBR | 46.43 Q | 0.202 | 
| 2 | 403 | Milton Campbell |  USA | 46.69 Q | 0.215 | 
| 3 | 107 | David Canal |  ESP | 47.08 Q | 0.156 | 
| 4 | 210 | Davian Clarke |  JAM | 47.17 | 0.218 | 
| 5 | 272 | Sunday Bada |  NGR | 48.14 | 0.147 | 
| 387 | Sofiane Labidi |  TUN | DQ | 0.176 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 209 | Danny McFarlane |  JAM | 46.68 Q PB | 0.169 | 
| 2 | 147 | Mark Hylton |  GBR | 46.87 Q | 0.213 | 
| 3 | 405 | James Davis |  USA | 46.90 Q | 0.188 | 
| 4 | 99 | Felix Sánchez |  DOM | 47.29 | 0.216 | 
| 5 | 325 | Boris Gorban |  RUS | 47.48 | 0.164 | 
| 6 | 371 | Jimisola Laursen |  SWE | 48.17 | 0.239 |