The men's 400 metres at the 1988 Summer Olympics in Seoul, South Korea took place between 24 and 28 September 1988.

The final, ran on Thursday September 28, 1988, started somewhat as expected, with Reynolds holding back and saving himself for his normal strong finish.

To the surprise of most watching a young American Steve Lewis went out strong from the start and gave Reynolds a run for his money.

The career of Lewis was blighted by injury although he did compete in the 1992 Summer Olympics in Barcelona, Spain, placing second in 400m and being part of the American quartet who took gold in 4 × 400 m relay.

The new American team was favored, however; Butch Reynolds had just broken the 20-year-old world record, and Danny Everett and Steve Lewis were strong contenders.

[2] Bangladesh, Honduras, Indonesia, the Maldives, Mali, Saint Vincent and the Grenadines, South Korea, Vanuatu, the (U.S.) Virgin Islands, and Zaire appeared in this event for the first time; the Republic of China had previously competed, but now appeared as Chinese Taipei for the first time.