Swimming at the 1948 Summer Olympics – Men's 100 metre freestyle
The men's 100 metre freestyle event at the 1948 Olympic Games took place between 30 and 31 July at the Empire Pool. This swimming event used freestyle swimming, which means that the method of the stroke is not regulated. Nearly all swimmers use the front crawl or a variant of that stroke. Because an Olympic-size swimming pool is 50 metres long, this race consisted of two lengths of the pool.
Competition format
The competition used a three-round format. The advancement rule was a modification of the one used since 1912, allowing the top swimmers in each race plus one or more wild cards to advance. For this event, the top two in each preliminary heat plus the next four fastest swimmers would advance to the semifinals; the top three in each semifinal plus the next two fastest swimmers would move on to the final. There were 6 heats of between 6 and 8 swimmers, allowing 16 swimmers to advance to the semifinals. The 2 semifinals had 8 swimmers each; 8 advanced to the final.Each race involved two lengths of the 50-metre pool.
Results
Heats
Heat 1
| Rank | Swimmer | Nation | Time | Notes |
| 1 | Alex Jany | 58.1 | ||
| 2 | Bruce Bourke | 59.1 | ||
| 3 | Elemér Szathmáry | 59.7 | ||
| 4 | Olle Johansson | 1:01.0 | ||
| 5 | Plauto Guimarães | 1:03.7 | ||
| 6 | Isidoro Pérez | 1:04.0 | ||
| 7 | Isaac Mansoor | 1:06.4 |
Heat 2
| Rank | Swimmer | Nation | Time | Notes |
| 1 | Keith Carter | 58.7 | ||
| 2 | Per-Olof Olsson | 59.0 | ||
| 3 | Zoltán Szilárd | 59.8 | ||
| 4 | Manuel Guerra | 1:00.7 | ||
| 5 | Augusto Cantón | 1:01.8 | ||
| 6 | Nicasio Silverio | 1:02.0 | ||
| 7 | Pat Kendall | 1:02.1 | ||
| 8 | Dilip Mitra | 1:06.9 |
Heat 3
| Rank | Swimmer | Nation | Time | Notes |
| 1 | Géza Kádas | 58.2 | ||
| 2 | Alberto Isaac | 1:00.1 | ||
| 3 | Warren Boyd | 1:00.4 | ||
| 4 | Ali Ahmed Bagdadi | 1:02.4 | ||
| 5 | Eric Jubb | 1:02.8 | ||
| 6 | Sachin Nag | 1:03.8 |
Heat 4
| Rank | Swimmer | Nation | Time | Notes |
| 1 | Horacio White | 1:00.2 | ||
| 2 | Aram Boghossian | 1:00.9 | ||
| 3 | Jesús Domínguez | 1:01.3 | ||
| 4 | Dorri El-Said | 1:02.5 | ||
| 5 | Fernand Martinaux | 1:04.2 | ||
| 6 | Panagiotis Khatzikyriakakis | 1:07.4 |
Heat 5
| Rank | Swimmer | Nation | Time | Notes |
| 1 | Wally Ris | 58.1 | ||
| 2 | Ronald Stedman | 1:01.3 | ||
| 3 | Henri Padou, Jr. | 1:01.5 | ||
| 4 | Sérgio Rodrigues | 1:01.6 | ||
| 5 | Wu Chuanyu | 1:03.5 | ||
| 6 | Derek Oatway | 1:08.6 |
Heat 6
| Rank | Swimmer | Nation | Time | Notes |
| 1 | Alan Ford | 59.2 | ||
| 2 | Taha Youssef El-Gamal | 59.7 | ||
| 3 | Martin Lundén | 1:00.2 | ||
| 4 | Peter Salmon | 1:01.0 | ||
| 5 | Ari Guðmundsson | 1:01.6 | ||
| 6 | Trevor Harrop | 1:02.3 | ||
| 7 | Raúl García | 1:02.5 | ||
| 8 | Walter Schneider | 1:05.1 |
Semifinals
Semifinal 1
| Rank | Swimmer | Nation | Time | Notes |
| 1 | Keith Carter | 57.6 | ||
| 2 | Alex Jany | 57.9 | ||
| 3 | Zoltán Szilárd | 59.6 | ||
| 4 | Taha Youssef El-Gamal | 59.9 | ||
| 5 | Bruce Bourke | 1:00.0 | ||
| 6 | Martin Lundén | 1:00.2 | ||
| 7 | Alberto Isaac | 1:00.4 | ||
| 8 | Aram Boghossian | 1:01.0 |
Semifinal 2
| Rank | Swimmer | Nation | Time | Notes |
| 1 | Wally Ris | 57.5 | , | |
| 2 | Alan Ford | 57.8 | ||
| 3 | Géza Kádas | 58.0 | ||
| 4 | Per-Olof Olsson | 59.1 | ||
| 5 | Horacio White | 1:00.4 | ||
| 6 | Elemér Szathmáry | 1:00.5 | ||
| 7 | Ronald Stedman | 1:01.0 | ||
| 8 | Warren Boyd | 1:01.1 |
Final
| Rank | Swimmer | Nation | Time | Notes |
| Wally Ris | 57.3 | |||
| Alan Ford | 57.8 | |||
| Géza Kádas | 58.1 | |||
| 4 | Keith Carter | 58.3 | ||
| 5 | Alex Jany | 58.3 | ||
| 6 | Per-Olof Olsson | 59.3 | ||
| 7 | Zoltán Szilárd | 59.6 | ||
| 8 | Taha Youssef El-Gamal | 1:00.5 |