Athletics at the 1920 Summer Olympics – Men's 400 metres

This was the sixth appearance of the event, which is one of 12 athletics events to have been held at every Summer Olympics. The only returning finalist from the pre-war 1912 Games was Ted Meredith of the United States, who had finished 4th in Stockholm and who had broken the world record in 1916. Other favored entrants included 1919 AAU champion Frank Shea of the United States, 1919 AAA champion Guy Butler of Great Britain, and 1920 AAA champion Bevil Rudd of South Africa.[2]

Czechoslovakia, Egypt, Estonia, Finland, India, Luxembourg, and Spain appeared in the event for the first time. The United States made its sixth appearance in the event, the only nation to compete in it at every Olympic Games to that point.

Despite the smaller field than 1912 (37 athletes, down from 49), the competition expanded from three rounds to four. The first round had 10 heats, with 3 or 4 runners each. The top two runners in each heat advanced to the quarterfinals. There were 4 quarterfinals, with 5 runners in each; the top three athletes in each heat advanced to the semifinals. The semifinals featured 2 heats of 6 runners each. Again, the top three runners in each semifinal heat advanced, making a six-man final.[2][3]

These were the standing world and Olympic records (in seconds) prior to the 1920 Summer Olympics.

World record	Ted Meredith (USA)	47.4(*)	Cambridge, United States	27 May 1916
Olympic record	Charles Reidpath (USA)	48.2	Stockholm, Sweden	13 July 1912

(*) 440 yards (= 402.34 m)

No records were set during this event.

• Belgium Olympic Committee (1957). Olympic Games Antwerp 1920: Official Report (in French).
• Wudarski, Pawel (1999). "Wyniki Igrzysk Olimpijskich" (in Polish). Retrieved 11 August 2007.