Athletics at the 2003 All-Africa Games – Men's 400 metres

The men's 400 metres at the 2003 All-Africa Games were held on October 11–13.

Heats
Qualification: First 4 of each heat (Q) and the next 4 fastest (q) qualified for the semifinals.

Semifinals
Qualification: First 2 of each semifinal (Q) and the next 2 fastest (q) qualified for the final.