Swimming at the 2017 World Aquatics Championships – 4 × 100 metre mixed medley relay
The 4 × 100 metre mixed medley relay competition at the 2017 World Championships was held on 26 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 |
| 26 July | Heat | 3:40.28 | , CR | |
| 26 July | Final | 3:38.56 | , CR |
Results
Heats
The heats were held at 10:52.Final
The final was held at 19:19.| Rank | Lane | Nation | Swimmers | Time | Notes |
| 4 | Matt Grevers Lilly King Caeleb Dressel Simone Manuel | 3:38.56 | |||
| 5 | Mitch Larkin Daniel Cave Emma McKeon Bronte Campbell | 3:41.21 | OC | ||
| 3 | Kylie Masse Richard Funk Penny Oleksiak Yuri Kisil | 3.41.25 | NR | ||
| 7 | Xu Jiayu Yan Zibei Zhang Yufei Zhu Menghui | 3:41.25 | AS | ||
| 5 | 6 | Georgia Davies Adam Peaty James Guy Siobhan-Marie O'Connor | 3:41.56 | ER | |
| 6 | 2 | Grigoriy Tarasevich Kirill Prigoda Svetlana Chimrova Veronika Popova | 3:43.02 | NR | |
| 7 | 8 | Lisa Graf Marco Koch Aliena Schmidtke Damian Wierling | 3:46.03 | ||
| 8 | 1 | Matteo Milli Nicolò Martinenghi Ilaria Bianchi Federica Pellegrini | 3.46.33 |