1977 European Athletics Indoor Championships – Men's 400 metres

The men's 400 metres event at the 1977 European Athletics Indoor Championships was held on 12 and 13 March in San Sebastián.

Heats
First 2 from each heat (Q) and the next 6 fastest (q) qualified for the semifinals.

Semifinals
First 2 from each heat (Q) and the next 2 fastest (q) qualified for the final.