| 1 | Ian Morris | TRI | 46,69 | Q |
| 2 | Roberto Hernandez | CUB | 46,74 | Q |
| 3 | Arjan Vissermann | NED | 46,89 | Q |
| 4 | Mark Henrich | FRG | 46,89 | |
| 5 | John Anzrah | KEN | 47,35 | |
| 6 | Moses Ugbisie | NGR | 47,41 |
| 1 | Antonio McKay | USA | 46,70 | Q |
| 2 | Michael Franks | USA | 46,78 | Q |
| 3 | Paul Harmsworth | GBR | 46,97 | Q |
| 4 | Allan Ingraham | BAH | 47,06 | |
| 5 | Momchil Charisanov | BUL | 47,18 | |
| 6 | Elvis Forde | BAR | 47,42 |