Athletics at the 1979 Pan American Games – Men's 400 metres hurdles

The men's 400 metres hurdles sprint competition of the athletics events at the 1979 Pan American Games took place at the Estadio Sixto Escobar. The defending Pan American Games champion was James King of the United States America.

Records
Prior to this competition, the existing world and Pan American Games records were as follows:

Final
Held on 8 July