Athletics at the 1984 Summer Olympics – Men's 400 metres hurdles
The men's 400 metres hurdles at the 1984 Summer Olympics in Los Angeles, California had an entry list of 45 competitors, with six qualifying heats and two semifinals before the final took place on Sunday August 5, 1984.
Edwin Moses won his second Olympic gold medal after 1976, while 18-year-old Danny Harris took the silver medal. Harald Schmid of West Germany took bronzeMedalists
Records
These were the standing World and Olympic records prior to the 1984 Summer Olympics.
| World Record | 47.02 |  Edwin Moses | Koblenz | August 31, 1983 |
| Olympic Record | 47.64 | Edwin Moses | Montreal | July 25, 1976 |
Final
| RANK | HEAT 1 | TIME |
| 1. | | 48.51 |
| 2. | | 48.94 |
| 3. | | 49.44 |
| 4. | | 49.79 |
| 5. | | 49.80 |
| 6. | | 50.08 |
| 7. | | 50.16 |
| 8. | | 50.70 |
| RANK | HEAT 2 | TIME |
| 1. | | 48.92 |
| 2. | | 49.03 |
| 3. | | 49.04 |
| 4. | | 49.36 |
| 5. | | 49.58 |
| 6. | | 49.89 |
| 7. | | 49.92 |
| 8. | | 50.06 |
Qualifying heats
| RANK | HEAT 1 | TIME |
| 1. | | 49.33 |
| 2. | | 49.85 |
| 3. | | 49.90 |
| 4. | | 50.25 |
| 5. | | 50.47 |
| 6. | | 50.99 |
| 7. | | 51.08 |
| 8. | | 51.27 |
| RANK | HEAT 2 | TIME |
| 1. | | 49.34 |
| 2. | | 49.66 |
| 3. | | 49.81 |
| 4. | | 50.05 |
| 5. | | 50.14 |
| 6. | | 50.39 |
| 7. | | 51.44 |
| RANK | HEAT 3 | TIME |
| 1. | | 49.88 |
| 2. | | 50.24 |
| 3. | | 50.27 |
| 4. | | 50.55 |
| 5. | | 51.39 |
| 6. | | 52.15 |
| 7. | | 53.62 |
| 8. | | 56.98 |
| RANK | HEAT 4 | TIME |
| 1. | | 49.51 |
| 2. | | 49.70 |
| 3. | | 49.77 |
| 4. | | 50.62 |
| 5. | | 51.14 |
| 6. | | 51.27 |
| 7. | | 52.85 |
| 8. | | 54.52 |
| RANK | HEAT 5 | TIME |
| 1. | | 49.94 |
| 2. | | 50.11 |
| 3. | | 50.46 |
| 4. | | 50.80 |
| 5. | | 51.47 |
| 6. | | 51.99 |
| 7. | | 54.36 |
| 8. | | 55.50 |
| RANK | HEAT 6 | TIME |
| 1. | | 49.81 |
| 2. | | 50.41 |
| 3. | | 51.02 |
| 4. | | 50.62 |
| 5. | | 51.45 |
| — | | DNF |
