| Date | 22 October 1968 — 10:00 | |
|---|---|---|
| Location | Alberca Olímpica Francisco Márquez, Ciudad de México | |
| Format | Fastest 8 advanced to the final round. | |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 3 | Andrey Dunayev | 5:01.9 | |||
| 2 | 5 | Martyn Woodroffe | 5:03.9 | |||
| 3 | 6 | Eduardo Alanís | 5:14.9 | |||
| 4 | 2 | Jacek Krawczyk | 5:15.1 | |||
| 4 | José Martínez | – | ||||
| – | Tony Asamli | – |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 5 | Greg Buckingham | 4:57.3 | |||
| 2 | 4 | Rafael Hernández | 5:01.1 | |||
| 3 | 2 | Hans Ljungberg | 5:06.1 | |||
| 4 | 7 | Vladimir Kravchenko | 5:08.7 | |||
| 5 | 1 | Tomás Becerra | 5:09.7 | |||
| 6 | 6 | Miguel Torres | 5:12.7 | |||
| 7 | 8 | Guðmundur Gíslason | 5:20.2 | |||
| 8 | 3 | Raúl Villagómez | 5:24.7 | |||
| – | Juan Carlos Bello | – |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 4 | Charlie Hickcox | 4:56.2 | |||
| 2 | 7 | Reinhard Merkel | 5:00.6 | |||
| 3 | 1 | Bernhard Mock | 5:07.1 | |||
| 4 | 3 | Péter Lázár | 5:10.6 | |||
| 5 | 2 | Angel Chakarov | 5:10.9 | |||
| 6 | 6 | Ken Campbell | 5:19.6 | |||
| 7 | 8 | Gershon Shefa | 5:22.6 | |||
| 8 | 5 | Lee Tong-Shing | 5:50.0 |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 1 | Mike Holthaus | 5:00.8 | |||
| 2 | 8 | George Smith | 5:04.4 | |||
| 3 | 5 | Yuliyan Rusev | 5:07.0 | |||
| 4 | 7 | Lars Kraus Jensen | 5:12.7 | |||
| 5 | 6 | Zbigniew Pacelt | 5:18.6 | |||
| 6 | 3 | Raymond Terrell | 5:19.5 | |||
| 7 | 4 | Francisco Ramis | 5:30.9 | |||
| 8 | 2 | Antonio Cruz | 5:31.1 |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 4 | Gary Hall | 4:56.2 | |||
| 2 | 3 | Sandy Gilchrist | 4:57.5 | |||
| 3 | 6 | Karl Byrom | 5:11.9 | |||
| 4 | 2 | Michele D'Oppido | 5:16.4 | |||
| 5 | 7 | Jacques Henrard | 5:17.0 | |||
| 6 | 5 | Olle Ferm | 5:18.9 | |||
| – | Bob Loh | – | ||||
| – | Amman Jalmaani | – |