2012 IAAF World Indoor Championships – Men's 400 metres

The men's 400 metres at the 2012 IAAF World Indoor Championships took place March 9 and 10 at the Ataköy Athletics Arena. The final was won by Costa Rican Nery Brenes in a time of 45.11.

Rabah Yousif of Sudan, who ran the heat and the semifinal, retrospectively got his results disqualified for doping.

Qualification: First 2 (Q) and the 6 fastest times qualified (q). 32 athletes from 27 countries participated.

Qualification: First 2 of each heat qualified (Q). 18 athletes from 14 countries participated.

6 athletes from 5 countries participated. The final started at 19:31.