| POS | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|
| 1 | Bershawn Jackson |  USA | 49.20 Q | 0.157 | 
| 2 | Pieter de Villiers |  RSA | 49.24 Q | 0.202 | 
| 3 | Mahau SUGUIMATI |  BRA | 49.45 Q | 0.170 | 
| 4 | Jonathan Williams |  BIZ | 49.61 q | 0.175 | 
| 5 | Kenji Narisako |  JPN | 49.63 | 0.163 | 
| 6 | Edivaldo Monteiro |  POR | 49.89 SB | 0.160 | 
| 7 | Harouna Garba |  NIG | 55.14 | 0.291 | 
| POS | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|
| 1 | Angelo Taylor |  USA | 48.67 Q | 0.158 | 
| 2 | Danny McFarlane |  JAM | 48.86 Q | 0.179 | 
| 3 | Alwyn Myburgh |  RSA | 48.92 Q SB | 0.148 | 
| 4 | Bayano Kamani |  PAN | 49.05 q SB | 0.174 | 
| 5 | Aleksandr Derevyagin |  RUS | 49.19 q | 0.187 | 
| 6 | Ibrahim Maïga |  MLI | 50.57 | 0.229 | 
| POS | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|
| 1 | Markino Buckley |  JAM | 48.65 Q PB | 0.196 | 
| 2 | L.J. van Zyl |  RSA | 48.86 Q | 0.179 | 
| 3 | Marek Plawgo |  POL | 49.17 Q | 0.169 | 
| 4 | Javier Culson |  PUR | 49.60 q | 0.246 | 
| 5 | Yan Meng |  CHN | 49.73 SB | 0.168 | 
| 6 | Aleksey Pogorelov |  KGZ | 51.47 | 0.200 | 
| POS | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|
| 1 | Kerron Clement |  USA | 49.42 Q | 0.240 | 
| 2 | PeriklÃs Iakovákis |  GRE | 49.50 Q | 0.178 | 
| 3 | Isa Phillips |  JAM | 49.55 Q | 0.225 | 
| 4 | Dai Tamesue |  JPN | 49.82 | 0.214 | 
| 5 | Felix Sánchez |  DOM | 51.10 | 0.184 | 
| 6 | Mowen Boino |  PNG | 51.47 SB | 0.250 | 
| Yevgeniy Meleshenko |  KAZ | DNF | 0.272 |