The men's 400 metres hurdles event at the Friendship Games was held on 17 and 18 August 1984 at the Grand Arena of the Central Lenin Stadium in Moscow, Soviet Union.
| width=200 bgcolor=gold | Gold | width=200 bgcolor=silver | Silver | width=200 bgcolor=CC9966 | Bronze |
| Aleksandr Vasilyev | Vladimir Budko | Toma Tomov Bulgaria |
| Rank | Heat | Name | Nationality | Time | Notes | |
|---|---|---|---|---|---|---|
| 1 | 2 | 49.77 | Q | |||
| 2 | 3 | 49.96 | Q | |||
| 3 | 2 | 50.18 | Q | |||
| 4 | 3 | 50.47 | Q | |||
| 5 | 2 | 50.48 | Q | |||
| 6 | 3 | 50.67 | Q | |||
| 7 | 3 | 50.80 | q | |||
| 8 | ? | q | ||||
| 9 | ? | F. Montiet | 51.29 | |||
| 10 | ? | 51.35 | ||||
| 11 | ? | 51.49 | ||||
| 12 | ? | 52.80 |
Out of competition performances
| Rank | Heat | Name | Nationality | Time | Notes | |
|---|---|---|---|---|---|---|
| 1 | 1 | 50.09 | ||||
| 2 | 1 | 50.24 | ||||
| 3 | 1 | 50.75 |
| Rank | Name | Nationality | Time | Notes | |
|---|---|---|---|---|---|
| 48.63 | |||||
| 48.74 | |||||
| 49.29 | |||||
| 4 | 49.67 | ||||
| 5 | 49.77 | ||||
| 6 | 50.44 | ||||
| 7 | 50.44 | ||||
| 8 | 50.68 |