The 400 metres at the 2006 Commonwealth Games as part of the athletics programme were held at the Melbourne Cricket Ground from Monday 20 March to Wednesday 22 March 2006.
The top two runners in each of the eight heats automatically qualified for the semifinals. The next eight fastest runners from across the heats also qualified. Those 24 runners competed in 3 semifinals, with the top two runners from each and next two fastest qualifying for the final.
Going into the event, the top ten Commonwealth athletes as ranked by the International Association of Athletics Federations were:
All times shown are in seconds.