Athletics at the 1984 Summer Olympics – Men's 400 metres hurdles

This was the 18th time the event was held. It had been introduced along with the men's 200 metres hurdles in 1900, with the 200 being dropped after 1904 and the 400 being held through 1908 before being left off the 1912 programme. However, when the Olympics returned in 1920 after World War I, the men's 400 metres hurdles was back and would continue to be contested at every Games thereafter.

One of the eight finalists from the 1980 Games returned: seventh-place finisher Franz Meier of Switzerland. Also returning was 1976 gold medalist Edwin Moses of the United States, who had not competed in 1980 due to the American-led boycott. Moses had not lost a 400 metres hurdles race since 26 August, 1977; he had won 89 consecutive finals since then, including the inaugural 1983 World Championship. There was little expectation that anyone would challenge Moses, but if anyone could it was thought to be Harald Schmid of West Germany—the winner in Moses's last loss seven years earlier, the runner-up at the World Championship, and the 1978 and 1982 European champion. Moses' teenage teammate Danny Harris was also an up-and-coming contender.[2]

The Bahamas, Bahrain, Cameroon, Egypt, the Ivory Coast, Jamaica, Mozambique, Paraguay, Rwanda, the Seychelles, and the United Arab Emirates each made their debut in the event. The United States made its 17th appearance, most of any nation, having missed only the boycotted 1980 Games.

The competition used the three-round format used every Games since 1908 (except the four-round competition in 1952): quarterfinals, semifinals, and a final. Ten sets of hurdles were set on the course. The hurdles were 3 feet (91.5 centimetres) tall and were placed 35 metres apart beginning 45 metres from the starting line, resulting in a 40 metres home stretch after the last hurdle. The 400 metres track was standard.

There were 6 quarterfinal heats with between 6 and 8 athletes each. The top 2 men in each quarterfinal advanced to the semifinals along with the next fastest 4 overall. The 16 semifinalists were divided into 2 semifinals of 8 athletes each, with the top 4 in each semifinal advancing to the 8-man final.[2]

These were the standing world and Olympic records (in seconds) prior to the 1984 Summer Olympics.

World record	Edwin Moses (USA)	47.02	Koblenz, West Germany	31 August 1983
Olympic record	Edwin Moses (USA)	47.64	Montreal, Canada	25 July 1976

No new world or Olympic records were set during the competition.

All times are Pacific Daylight Time (UTC-7)

• Athletics at the Friendship Games – Men's 400 metres hurdles