Athletics at the 1968 Summer Olympics – Men's 400 metres

This was the sixteenth appearance of the event, which is one of 12 athletics events to have been held at every Summer Olympics. Andrzej Badeński of Poland, who had won bronze in 1964, was the only finalist from the Tokyo Games to compete again in 1968. The United States team was "dominant in this event in 1968"; Larry James held the world record at 44.1 seconds, Lee Evans was the AAU and NCAA champion, and even the third member of the team, Ron Freeman, ran well below Olympic record time at the U.S. trials.[2]

Barbados, the Dominican Republic, El Salvador, Morocco, Nicaragua, and Sudan appeared in this event for the first time. The federation of Malaysia also competed for the first time, though Malaya had previously appeared. East and West Germany competed separately for the first time. The United States made its sixteenth appearance in the event, the only nation to compete in it at every Olympic Games to that point.

The competition retained the basic four-round format from 1920. The "fastest loser" system, introduced in 1964, was available but not used in 1968 because there was no need to balance quarterfinals as there were 8 heats in the first round. Those heats each had between 6 and 8 athletes, with the top four advancing. The 4 quarterfinals each had 8 runners; the top four athletes in each quarterfinal heat advanced to the semifinals. The semifinals featured 2 heats of 8 runners each. The top four runners in each semifinal heat advanced, making an eight-man final.[2][3]

Prior to the competition, the existing World and Olympic records were as follows.

World record	Larry James (USA)	44.1	Echo Summit, United States	14 September 1968
Olympic record	Otis Davis (USA)	44.9	Rome, Italy	6 September 1960

Lee Evans broke the Olympic record with a 44.8 second run in the second semifinal; both Larry James and Martin Jellinghaus matched the old record in that same semifinal. All three Americans broke the new record in the final, with Evans (43.8 seconds) and James (43.9 seconds) also coming in under the world record time. Evans' auto-timed result of 43.86 seconds was not official under the rules at that point (which used hand-timed results) but was later recognized as the initial world record upon the switch to automatic timing as official in 1977.

The quarterfinals were held on the second day (with the semifinals) rather than the first day (with the first round heats), a change from previous years.

All times are Central Standard Time (UTC-6)

• Official report