In the fourth day of swimming in the world aquatic championships, Adam Peaty took two gold medals – one in the 50 meters breaststroke and the other in the mixed 4×100 meters medley relay. Sun Yang of China won the men’s 800 meters freestyle again, Laszlo Cseh took gold in the men’s 200 meters butterfly and Katie Ledecky now has three gold medals from the Kazan meet after winning the women’s 200 meters freestyle.
Men’s 800 meters freestyle – Sun Yang of China won the event, swimming a 7:39.96 to pick up his 7th gold medal in World Championships and his second of Kazan. Gregorio Paltrinieri of Italy took silver, setting a new European record with 7:40.81, winning his first medal in Kazan. Mark Horton of Australia took bronze after swimming 7:44.02, as the 19-year old picked up his first world championships medal.
Men’s 50 meters breaststroke – Adam Peaty of Great Britain completed his 50-100 double in Kazan, swimming a 26.51. Once again, it was South African Cameron van der Burgh taking silver with a 26.66. Kevin Cordes of the United States took bronze after swimming 26.86.
Men’s 200 meters butterfly – The never ending László Cseh of Hungary (29 years old) took his second gold medal ever in the world’s, the previous one coming in 2005. He swam a 1:53.48, leaving behind Chad le Clos with a 1:53.68, unable to defend his title from 2013. Jan Świtkowski of Poland took Bronze, swimming a 1:54.10.
Women’s 200 meters freestyle – Katie Ledecky won her third gold medal of the meet and seventh of her career by winning a new event for her, swimming a 1:55.16. Federica Pellegrini of Italy took silver after swimming a 1:55.32, finishing second in the event for the second consecutive time. Missy Franklin of the United States took bronze, swimming 1:55.49. It’s her second bronze of the Kazan meet and overall 13th medal in the world championships.
Mixed 4 x 100 meters medley relay – A new event, won by the Brits (Chris Walker-Hebborn, Adam Peaty, Siobhan-Marie O’Connor, Fran Halsall), swimming 3:41.71, a new world record. The United States took silver with 3:43.27 and Germany took bronze, swimming a 3:44.13. For Peaty and for Cordes of the United States it was a day of winning two medals.
Medal Table
| Rank | Nation | Gold | Silver | Bronze | Total |
|---|---|---|---|---|---|
| 1 |  Great Britain |
4 | 1 | 2 | 7 |
| 2 |  United States |
3 | 1 | 4 | 8 |
| 3 |  Australia |
3 | 1 | 2 | 6 |
| 4 |  China |
2 | 1 | 1 | 4 |
| 5 |  France |
2 | 1 | 0 | 3 |
| 6 |  Hungary |
2 | 0 | 2 | 4 |
| 7 |  Russia* |
1 | 1 | 0 | 2 |
| 8 |  Sweden |
1 | 0 | 0 | 1 |
| 9 |  South Africa |
0 | 3 | 0 | 3 |
| 10 |  Italy |
0 | 2 | 1 | 3 |
| 11 |  Netherlands |
0 | 2 | 0 | 2 |
| 12 |  Denmark |
0 | 1 | 1 | 2 |
| 13 |  Brazil |
0 | 1 | 0 | 1 |
 Japan |
0 | 1 | 0 | 1 | |
 Lithuania |
0 | 1 | 0 | 1 | |
 New Zealand |
0 | 1 | 0 | 1 | |
| 17 |  Germany |
0 | 0 | 2 | 2 |
 Poland |
0 | 0 | 2 | 2 | |
| 19 |  Canada |
0 | 0 | 1 | 1 |
 Jamaica |
0 | 0 | 1 | 1 |