The men's 400 metres hurdles at the 1988 Summer Olympics in Seoul, South Korea had an entry list of 38 competitors, with five qualifying heats (38 runners) and two semifinals (16) before the final (8) took place on Sunday September 25, 1988.

Dia Ba broke up a potential American sweep, as 1976 and 1984 champion Edwin Moses took bronze and Kevin Young placed fourth.

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.

No longer unbeatable, Moses had still won the 1987 World Championships and the 1988 U.S. Olympic trials—both featured very strong fields.

[2] Barbados, Fiji, Honduras, Nepal, Sierra Leone, and South Korea each made their debut in the event.