Swimming at the 2017 World Aquatics Championships – 4 × 100 metre mixed freestyle relay
The 4 × 100 metre mixed freestyle relay competition at the 2017 World Championships was held on 29 July 2017.
Records
Prior to the competition, the existing world and championship records were as follows.The following new records were set during this competition
| Date | Event | Nation | Time | Record |
| 29 July | Final | 3:19.60 | , CR |
Results
Heats
The heats were held at 10:21.Final
The final was held at 19:17.| Rank | Lane | Nation | Swimmers | Time | Notes |
| 5 | Caeleb Dressel Nathan Adrian Mallory Comerford Simone Manuel | 3:19.60 | WR | ||
| 4 | Ben Schwietert Kyle Stolk Femke Heemskerk Ranomi Kromowidjojo | 3:21.81 | ER | ||
| 3 | Yuri Kisil Javier Acevedo Chantal Van Landeghem Penny Oleksiak | 3:23.55 | NR | ||
| 4 | 7 | Katsuhiro Matsumoto Katsumi Nakamura Rikako Ikee Chihiro Igarashi | 3:24.78 | AS | |
| 5 | 2 | Luca Dotto Alessandro Miressi Federica Pellegrini Silvia Di Pietro | 3:24.89 | ||
| 6 | 6 | Dominik Kozma Richárd Bohus Zsuzsanna Jakabos Evelyn Verrasztó | 3:25.02 | NR | |
| 7 | 1 | Danila Izotov Aleksandr Popkov Viktoriya Andreyeva Veronika Popova | 3:25.49 | NR | |
| 8 | 8 | Louis Townsend Alexander Graham Brittany Elmslie Madison Wilson | 3:25.51 |