Swimming at the 1979 Pan American Games – Women's 400 metre individual medley

The women's 400 metre individual medley competition of the swimming events at the 1979 Pan American Games took place on 5 July at the Piscina Olimpica Del Escambron. The last Pan American Games champion was Kathy Heddy of US.

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.

Heats
The first round was held on July 5.

Final
The final was held on July 5.