The men's 400 metres at the 2008 Summer Olympics took place on 18–21 August at the Beijing National Stadium. Fifty-five athletes from 40 nations competed. The event was won by LaShawn Merritt of the United States, in what would ultimately be the final of seven consecutive American victories stretching from 1984 to 2008; it was the 19th overall title in the event by the United States. Jeremy Wariner took silver to become the fourth man to win two medals in the event, though Merritt kept him from matching Michael Johnson's pair of golds. David Neville's bronze completed the American podium sweep, the second consecutive sweep in the event and the fifth overall (1904, 1968, 1988, 2004).