| POS | Rank | Heat | ATHLETE | COUNTRY | RESULTS |
|---|---|---|---|---|---|
| 1 | 1 | 3 | LaShawn Merritt |
USA |
44.12 Q |
| 2 | 1 | 1 | Jeremy Wariner |
USA |
44.15 Q |
| 3 | 2 | 1 | Chris Brown |
BAH |
44.59 Q |
| 4 | 2 | 3 | Martyn ROONEY |
GBR |
44.60 Q PB |
| 5 | 3 | 3 | Johan Wissman |
SWE |
44.64 q SB |
| 6 | 1 | 2 | Leslie Djhone |
FRA |
44.79 Q SB |
| 7 | 4 | 3 | Renny QUOW |
TTO |
44.82 q PB |
| 8 | 3 | 1 | Kévin BORLÉE |
BEL |
44.88 NR |
| 9 | 2 | 2 | David Neville |
USA |
44.91 Q |
| 10 | 5 | 3 | Gary Kikaya |
COD |
44.94 |
| 10 | 4 | 1 | Nery Brenes |
CRC |
44.94 NR |
| 12 | 5 | 1 | Saul Welgopwa |
NGR |
45.02 SB |
| 13 | 3 | 2 | Joel Milburn |
AUS |
45.06 |
| 13 | 6 | 1 | Williams Collazo |
CUB |
45.06 PB |
| 15 | 4 | 2 | Ricardo Chambers |
JAM |
45.09 |
| 16 | 5 | 2 | Jonathan BORLÉE |
BEL |
45.11 PB |
| 17 | 7 | 1 | Tabarie Henry |
ISV |
45.19 NR |
| 18 | 6 | 2 | James Godday |
NGR |
45.24 |
| 19 | 7 | 2 | Andretti Bain |
BAH |
45.52 |
| 20 | 6 | 3 | Michael Mathieu |
BAH |
45.56 |
| 20 | 7 | 3 | Sean Wroe |
AUS |
45.56 |
| 22 | 8 | 2 | Andrew Steele |
GBR |
45.59 |
| 23 | 8 | 1 | Claudio Licciardello |
ITA |
45.64 |
| 24 | 8 | 3 | Cedric van Branteghem |
BEL |
45.81 |