Swimming at the 2017 World Aquatics Championships – Women's 400 metre individual medley

Prior to the competition, the existing world and championship records were as follows.

World record	Katinka Hosszú (HUN)	4:26.36	Rio de Janeiro, Brazil	6 August 2016
Competition record	Katinka Hosszú (HUN)	4:30.31	Rome, Italy	26 July 2009

The following new records were set during this competition.

Date	Event	Name	Nationality	Time	Record
30 July	Final	Katinka Hosszú	Hungary	4:29.33	CR

The heats were held at 09:30.^[3]

Rank	Heat	Lane	Name	Nationality	Time	Notes
1	3	4	Katinka Hosszú	Hungary	4:33.90	Q
2	3	5	Mireia Belmonte	Spain	4:35.29	Q
3	3	3	Elizabeth Beisel	United States	4:36.18	Q
4	2	6	Sydney Pickrem	Canada	4:36.25	Q
5	3	6	Sakiko Shimizu	Japan	4:36.43	Q
6	2	3	Leah Smith	United States	4:36.94	Q
7	2	4	Yui Ohashi	Japan	4:36.97	Q
8	2	5	Hannah Miley	Great Britain	4:37.14	Q
9	3	2	Kim Seo-yeong	South Korea	4:39.80
10	3	7	Nguyễn Thị Ánh Viên	Vietnam	4:40.39
11	2	8	Joanna Maranhão	Brazil	4:41.29
12	2	1	Zsuzsanna Jakabos	Hungary	4:41.40
13	3	1	Zhou Min	China	4:42.26
14	3	0	Viktoriya Zeynep Güneş	Turkey	4:42.27
15	2	9	Ye Shiwen	China	4:43.40
16	1	3	Kaylee McKeown	Australia	4:43.61
17	2	0	Victoria Kaminskaya	Portugal	4:44.96
18	3	8	Barbora Závadová	Czech Republic	4:46.75
19	2	2	Mary-Sophie Harvey	Canada	4:46.88
20	2	7	Abbie Wood	Great Britain	4:47.30
21	1	6	Monika González	Mexico	4:48.00
22	3	9	Anja Crevar	Serbia	4:48.53
23	1	5	Helena Gasson	New Zealand	4:49.35
24	1	4	Virginia Bardach	Argentina	4:53.22
25	1	2	Ilektra Lebl	Greece	4:56.95
26	1	7	Azzahra Permatahani	Indonesia	4:57.00
27	1	1	Sara Nysted	Faroe Islands	5:21.21
	1	8	Sayani Ghosh	India	DNS

The final was held at 18:20.^[4]

Rank	Lane	Name	Nationality	Time	Notes
	4	Katinka Hosszú	Hungary	4:29.33	CR
	5	Mireia Belmonte	Spain	4:32.17
	6	Sydney Pickrem	Canada	4:32.88
4	1	Yui Ohashi	Japan	4:34.50
5	2	Sakiko Shimizu	Japan	4:35.62
6	7	Leah Smith	United States	4:36.09
7	3	Elizabeth Beisel	United States	4:37.63
8	8	Hannah Miley	Great Britain	4:38.34