Swimming at the 2019 World Aquatics Championships – Men's 400 metre individual medley

The Men's 400 metre individual medley competition at the 2019 World Championships was held on 28 July 2019.

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

Heats
The heats were held at 10:00.

Final
The final was held on 28 July at 21:01.