| Event: | Men's 400 metres |
| Competition: | European Athletics Championships |
The men's 400 metres at the 1978 European Athletics Championships was held in Prague, then Czechoslovakia, at Stadion Evžena Rošického on 30 and 31 August, and 1 September 1978.
| Gold | Franz-Peter Hofmeister | |
| Silver | Karel Kolář | |
| Bronze | Francis Demarthon |
1 September
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| align=left | align=left | 45.73 | |||||
| align=left | align=left | 45.77 | NR | ||||
| align=left | align=left | | 45.97 | ||||
| 4 | align=left | align=left | 46.22 | ||||
| 5 | align=left | align=left |  | 46.23 | |||
| 6 | align=left | align=left | | 46.34 | |||
| 7 | align=left | align=left | 46.69 | ||||
| align=left | align=left |  | DNS |
31 August
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 46.27 | Q | ||
| 2 | align=left | align=left | 46.28 | Q | |||
| 3 | align=left | align=left | 46.33 | Q | |||
| 4 | align=left | align=left | | 46.69 | Q | ||
| 5 | align=left | align=left | | 46.91 | |||
| 6 | align=left | align=left |  | 47.17 | |||
| 7 | align=left | align=left |  | 47.18 | |||
| 8 | align=left | align=left | | 47.50 |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 46.09 | Q | |||
| 2 | align=left | align=left | 46.18 | Q | |||
| 3 | align=left | align=left | | 46.26 | Q | ||
| 4 | align=left | align=left | | 46.32 | Q | ||
| 5 | align=left | align=left | 46.37 | ||||
| 6 | align=left | align=left | | 46.59 | |||
| 7 | align=left | align=left | 46.91 | ||||
| 8 | align=left | align=left | 47.35 |
30 August
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 46.33 | Q | |||
| 2 | align=left | align=left | | 46.75 | Q | ||
| 3 | align=left | align=left | 47.18 | Q | |||
| 4 | align=left | align=left | 47.51 | ||||
| 5 | align=left | align=left | | 47.91 | |||
| 6 | align=left | align=left |  | 48.71 | |||
| 7 | align=left | align=left | | 53.05 |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 46.28 | Q | |||
| 2 | align=left | align=left | | 46.63 | Q | ||
| 3 | align=left | align=left | 46.77 | Q | |||
| 4 | align=left | align=left | | 46.94 | q | ||
| 5 | align=left | align=left | | 47.27 | q | ||
| 6 | align=left | align=left | 47.65 |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 46.57 | Q | |||
| 2 | align=left | align=left | | 46.73 | Q | ||
| 3 | align=left | align=left | | 47.05 | Q | ||
| 4 | align=left | align=left | 47.28 | q | |||
| 5 | align=left | align=left | | 47.55 | |||
| 6 | align=left | align=left |  | 48.02 |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 46.50 | Q | |||
| 2 | align=left | align=left | | 46.61 | Q | ||
| 3 | align=left | align=left | | 46.81 | Q | ||
| 4 | align=left | align=left | | 47.03 | q | ||
| 5 | align=left | align=left | | 47.33 | |||
| 6 | align=left | align=left | 47.59 |
According to an unofficial count, 25 athletes from 14 countries participated in the event.
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