| Date | 17 August 2004 | |
|---|---|---|
| Location | Olympiako Kentro Ugrou Stivou, Olympiako Athletiko Kentro Athinon Spiros Loues, Athina (Main Pool) | |
| Format | Fastest 8 advanced to the final round. | |
| Pos | Lane | Competitor | NOC | Time | |||
|---|---|---|---|---|---|---|---|
| 1 | 1 | Roland Schoeman |  RSA | 48.39 | |||
| 2 | 4 | Pieter van den Hoogenband |  NED | 48.55 | |||
| 3 | 7 | Filippo Magnini |  ITA | 48.91 | |||
| 4 | 2 | Andrey Kapralov |  RUS | 49.12 | |||
| 5 | 8 | Salim Iles |  ALG | 49.13 | |||
| 6 | 5 | Duje Draganja |  CRO | 49.14 | |||
| 7 | 5 | Ryk Neethling | RSA | 49.18 | |||
| 8 | 3 | Ian Thorpe |  AUS | 49.21 | |||
| 9 | 6 | Aleksandr Popov | RUS | 49.23 | |||
| 10 | 3 | Fréd Bousquet |  FRA | 49.25 | |||
| 11 | 7 | George Bovell |  TTO | 49.53 | |||
| 12 | 6 | Romain Barnier | FRA | 49.63 | |||
| 13 | 2 | Peter Mankoč |  SLO | 49.71 | |||
| 14 | 4 | Rolandas Gimbutis |  LTU | 49.75 | |||
| 15 | 1 | Luis Rojas |  VEN | 49.85 | |||
| 16 | 8 | Torsten Spanneberg |  GER | 49.88 |
| Time | 19:30 |
|---|
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 8 | Salim Iles | ALG | 49.13 | ||
| 2 | 5 | Duje Draganja | CRO | 49.14 | ||
| 3 | 3 | Ian Thorpe | AUS | 49.21 | ||
| 4 | 6 | Aleksandr Popov | RUS | 49.23 | ||
| 5 | 7 | George Bovell | TTO | 49.53 | ||
| 6 | 2 | Peter Mankoč | SLO | 49.71 | ||
| 7 | 4 | Rolandas Gimbutis | LTU | 49.75 | ||
| 8 | 1 | Luis Rojas | VEN | 49.85 |
| Time | 19:37 |
|---|
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 1 | Roland Schoeman | RSA | 48.39 | ||
| 2 | 4 | Pieter van den Hoogenband | NED | 48.55 | ||
| 3 | 7 | Filippo Magnini | ITA | 48.91 | ||
| 4 | 2 | Andrey Kapralov | RUS | 49.12 | ||
| 5 | 5 | Ryk Neethling | RSA | 49.18 | ||
| 6 | 3 | Fréd Bousquet | FRA | 49.25 | ||
| 7 | 6 | Romain Barnier | FRA | 49.63 | ||
| 8 | 8 | Torsten Spanneberg | GER | 49.88 |
