Swimming at the 1964 Summer Olympics – Women's 400 metre individual medley
The women's 400 metre individual medley event at the 1964 Summer Olympics took place on 15–17 October. This swimming event used medley swimming and this was the first time for this event in this distance for the women swimmers. Because an Olympic size swimming pool is 50 metres long, this race consisted of eight lengths of the pool. The first two lengths were swum using the butterfly stroke, the second pair with the backstroke, the third pair of lengths in breaststroke, and the final two were freestyle. Unlike other events using freestyle, swimmers could not use butterfly, backstroke, or breaststroke for the freestyle leg; most swimmers use the front crawl in freestyle events.Medalists
Results
Heats
Heat 1
| Rank | Athlete | Country | Time | Note |
| 1 | Anita Lonsbrough | | 5:30.6 | |
| 2 | Sharon Finneran | | 5:32.7 | |
| 3 | Márta Egerváry | | 5:35.8 | |
| 4 | Helga Zimmermann | | 5:38.9 | |
| 5 | Jane Cortis | | 5:43.6 | |
Heat 2
| Rank | Athlete | Country | Time | Note |
| 1 | Martha Randall | | 5:27.8 | |
| 2 | Barbara Hounsell | | 5:38.4 | |
| 3 | Adrie Lasterie | | 5:41.3 | |
| 4 | Harriet Blank | | 5:42.4 | |
| 5 | Isabel Castañe | | 5:50.7 | |
| 6 | Margaret Harding | | 6:10.7 | |
Heat 3
| Rank | Athlete | Country | Time | Note |
| 1 | Veronika Holletz | | 5:26.8 | |
| 2 | Betty Heukels | | 5:32.4 | |
| 3 | Linda McGill | | 5:38.3 | |
| 4 | Kimiko Ezaka | | 5:42.1 | |
| 5 | Kirsten Strange-Campbell | | 5:44.4 | |
| 6 | Pamela Johnson | | 6:11.9 | |
Heat 4
| Rank | Athlete | Country | Time | Note |
| 1 | Donna de Varona | | 5:24.2 | |
| 2 | Marianne Heemskerk | | 5:38.6 | |
| 3 | Helen Kennedy | | 5:49.9 | |
| 4 | Natsuko Matsuda | | 5:51.5 | |
| 5 | Silvia Belmar | | 6:00.7 | |
Final
| Rank | Athlete | Country | Time | Notes |
| Donna de Varona | | 5:18.7 | OR |
| Sharon Finneran | | 5:24.1 | |
| Martha Randall | | 5:24.2 | |
| 4 | Veronika Holletz | | 5:25.6 | |
| 5 | Linda McGill | | 5:28.4 | |
| 6 | Betty Heukels | | 5:30.3 | |
| 7 | Anita Lonsbrough | | 5:30.5 | |
| 8 | Márta Egerváry | | 5:38.4 | |
Key: OR = Olympic record
