Swimming at the 2001 World Aquatics Championships – Men's 800 metre freestyle

The men's 800 metre freestyle event at the 2001 World Aquatics Championships took place 24 July. The heats took place 23 July, and the final was held on 24 July.

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

The following record was established during the competition:

Final
Key: WR = World record