Swimming at the 1991 Pan American Games – Men's 400 metre individual medley

The men's 400 metre individual medley competition of the swimming events at the 1991 Pan American Games took place on 13 August. The last Pan American Games champion was Jerry Frentsos of the United States.

This race consisted of eight lengths of the pool. The first two lengths were swum using the butterfly stroke, the second pair with the backstroke, the third pair of lengths in breaststroke, and the final two were freestyle.

Results
All times are in minutes and seconds.

Final
The final was held on August 13.