1987 IAAF World Indoor Championships – Men's 400 metres

The men's 400 metres event at the 1987 IAAF World Indoor Championships was held at the Hoosier Dome in Indianapolis on 6 and 7 March.

Heats
The first 2 of each heat (Q) and next 4 fastest (q) qualified for the semifinals.

Semifinals
First 3 of each semifinal (Q) qualified directly for the final.