# 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.
| World record | United States | 3:23.05 | Kazan, Russia | 8 August 2015 |
| Competition record | United States | 3:23.05 | Kazan, Russia | 8 August 2015 |
The following new records were set during this competition
| Date | Event | Nation | Time | Record |
| 29 July | Final | United States | 3:19.60 | WR, CR |

## Results
### Heats

The heats were held at 10:21.
| Rank | Heat | Lane | Nation | Swimmers | Time | Notes |
| 1 | 3 | 4 | Netherlands | Ben Schwietert (48.97) Kyle Stolk (48.06) Femke Heemskerk (52.77) Maud van der Meer (54.09) | 3:23.89 | Q |
| 2 | 1 | 6 | United States | Blake Pieroni (48.23) Townley Haas (48.32) Lia Neal (53.98) Kelsi Worrell (53.40) | 3:23.93 | Q |
| 3 | 3 | 7 | Canada | Yuri Kisil (48.57) Markus Thormeyer (49.35) Sandrine Mainville (53.75) Chantal Van Landeghem (53.40) | 3:25.07 | Q |
| 4 | 3 | 3 | Hungary | Dominik Kozma (48.25) Nándor Németh (48.61) Zsuzsanna Jakabos (54.18) Evelyn Verrasztó (54.41) | 3:25.45 | Q, NR |
| 5 | 2 | 4 | Italy | Alessandro Miressi (48.51) Ivano Vendrame (48.54) Federica Pellegrini (53.80) Erika Ferraioli (54.86) | 3:25.71 | Q |
| 6 | 2 | 7 | Japan | Katsuhiro Matsumoto (49.42) Katsumi Nakamura (47.98) Tomomi Aoki (54.86) Chihiro Igarashi (54.65) | 3:26.91 | Q, AS |
| 7 | 2 | 5 | Russia | Nikita Korolev (49.27) Aleksandr Popkov (48.48) Viktoriya Andreyeva (54.63) Veronika Popova (54.56) | 3:26.94 | Q |
| 8 | 3 | 0 | Australia | Louis Townsend (49.42) Zac Incerti (49.03) Brianna Throssell (54.74) Madison Wilson (54.30) | 3:27.49 | Q |
| 9 | 2 | 1 | China | Lin Yongqing (49.26) Cao Jiwen (49.92) Wu Qingfeng (55.15) Sun Meichen (55.09) | 3:29.42 | |
| 10 | 3 | 9 | Denmark | Anders Lie (49.70) Daniel Skaaning (49.87) Signe Bro (54.79) Emilie Beckmann (55.77) | 3:30.13 | |
| 11 | 1 | 3 | Israel | Marcus Schlesinger (50.80) Liran Konovalov (50.27) Keren Siebner (56.14) Andrea Murez (53.95) | 3:31.16 | |
| 12 | 2 | 6 | South Africa | Douglas Erasmus (50.02) Zane Waddell (48.85) Erin Gallagher (55.26) Emma Chellius (57.25) | 3:31.38 | AF |
| 13 | 1 | 2 | Luxembourg | Julien Henx (50.22) Pit Brandenburger (51.02) Julie Meynen (55.93) Monique Olivier (57.73) | 3:34.90 | |
| 14 | 1 | 4 | Latvia | Uvis Kalniņš (50.50) Girts Feldberg (50.83) Gabriela Ņikitina (56.76) Kristina Steina (1:00.27) | 3:38.36 | |
| 15 | 3 | 6 | Jordan | Khader Baqlah (49.46) Mohammed Bedour (50.47) Talita Baqlah (1:00.69) Dara Al-Bakry (59.69) | 3:40.31 | |
| 16 | 3 | 8 | Macau | Chao Man Hou (52.33) Lin Sizhuang (52.45) Tan Chi Yan (59.37) Lei On Kei (59.34) | 3:43.49 | |
| 17 | 3 | 1 | Aruba | Mikel Schreuders (49.80) Jordy Groters (53.10) Allyson Ponson (59.87) Daniella van den Berg (1:01.17) | 3:43.94 | |
| 18 | 1 | 7 | Seychelles | Dean Hoffman (55.23) Alexus Laird (1:00.82) Adam Moncherry (57.93) Felicity Passon (58.29) | 3:52.27 | |
| 19 | 2 | 9 | Madagascar | Heriniavo Rasolonjatovo (54.29) Andrianirina Lalanomena (59.04) Elodie Marion Razafy (1:03.53) Hantan Raharvel (1:02.53) | 3:59.39 | |
| 20 | 2 | 2 | Tajikistan | Olim Kurbanov (59.51) Ramziyor Khorkashov (1:05.14) Karina Klimyk (1:13.55) Anastasiya Tyurina (1:11.45) | 4:29.65 | |
| 21 | 3 | 2 | Maldives | Ismail Muthasim Adnan (1:02.06) Aminath Shajan (1:12.51) Sajina Aishath (1:15.35) Mubal Azzam Ibrahim (1:01.32) | 4:31.24 | |
| | 1 | 5 | Slovakia | DNS | DNS | DNS |
| | 2 | 0 | Faroe Islands | DNS | DNS | DNS |
| | 2 | 3 | Egypt | DNS | DNS | DNS |
| | 2 | 8 | Sri Lanka | DNS | DNS | DNS |
| | 3 | 5 | France | DNS | DNS | DNS |

### Final

The final was held at 19:17.
| Rank | Lane | Nation | Swimmers | Time | Notes |
| | 5 | United States | Caeleb Dressel (47.22) Nathan Adrian (47.49) Mallory Comerford (52.71) Simone Manuel (52.18) | 3:19.60 | WR |
| | 4 | Netherlands | Ben Schwietert (49.12) Kyle Stolk (47.80) Femke Heemskerk (52.33) Ranomi Kromowidjojo (52.56) | 3:21.81 | ER |
| | 3 | Canada | Yuri Kisil (48.51) Javier Acevedo (48.68) Chantal Van Landeghem (53.25) Penny Oleksiak (53.11) | 3:23.55 | NR |
| 4 | 7 | Japan | Katsuhiro Matsumoto (49.38) Katsumi Nakamura (47.76) Rikako Ikee (53.50) Chihiro Igarashi (54.14) | 3:24.78 | AS |
| 5 | 2 | Italy | Luca Dotto (48.71) Alessandro Miressi (48.27) Federica Pellegrini (53.49) Silvia Di Pietro (54.42) | 3:24.89 | |
| 6 | 6 | Hungary | Dominik Kozma (48.12) Richárd Bohus (48.54) Zsuzsanna Jakabos (53.60) Evelyn Verrasztó (54.76) | 3:25.02 | NR |
| 7 | 1 | Russia | Danila Izotov (48.59) Aleksandr Popkov (48.48) Viktoriya Andreyeva (54.66) Veronika Popova (53.76) | 3:25.49 | NR |
| 8 | 8 | Australia | Louis Townsend (49.24) Alexander Graham (48.36) Brittany Elmslie (53.93) Madison Wilson (53.98) | 3:25.51 | |