Athletics at the 2023 Pan American Games – Men's 400 metres

The men's 400 metres competition of the athletics events at the 2023 Pan American Games was held on October 30 and November 2 at the Julio Martínez National Stadium of Santiago, Chile.

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

Results
All times shown are in seconds.

Semifinal
Qualification: First 2 in each heat (Q) and next 2 fastest (q) qualified for the final. The results were as follows:

Final
The results were as follows: