1989 IAAF World Indoor Championships – Men's 400 metres

The men's 400 metres event at the 1989 IAAF World Indoor Championships was held at the Budapest Sportcsarnok in Budapest on 4 and 5 March 1989.

The winning margin was 0.50 seconds which as of July 2024 remains the greatest winning margin in the men's 400 metres at these championships.

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

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