The Men's 400 metres event at the 2013 European Athletics U23 Championships was held in Tampere, Finland, at Ratina Stadium on 11 and 12 July.
| Gold | Lev Mosin | |
| Silver | Vitaliy Butrym | |
| Bronze | Nikita Uglov |
12 July 2013
| Rank | Name | Nationality | Lane | Reaction Time | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|---|
| align=left | align=left | | 3 | 0.158 | 45.51 | PB | |||
| align=left | align=left | | 6 | 0.157 | 45.88 | PB | |||
| align=left | align=left | | 4 | 0.187 | 46.04 | SB | |||
| 4 | align=left | align=left | 7 | 0.146 | 46.05 | ||||
| 5 | align=left | align=left | 5 | 0.178 | 46.35 | ||||
| 6 | align=left | align=left |  | 8 | 0.168 | 46.47 | SB | ||
| 7 | align=left | align=left |  | 1 | 0.158 | 46.61 | |||
| 8 | align=left | align=left |  | 2 | 0.170 | 47.80 |
Qualified: First 2 in each heat (Q) and 2 best performers (q) advance to the Final
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 46.20 | Q | ||
| 2 | align=left | align=left | 46.26 | Q PB | |||
| 3 | align=left | align=left | | 46.35 | Q | ||
| 4 | align=left | align=left | | 46.57 | q PB | ||
| 5 | align=left | align=left | | 46.58 | q | ||
| 6 | align=left | align=left | | 46.67 | Q | ||
| 7 | align=left | align=left | 46.67 | Q | |||
| 8 | align=left | align=left | | 46.71 | Q | ||
| 9 | align=left | align=left | 46.97 | ||||
| 10 | align=left | align=left |  | 46.98 | |||
| 10 | align=left | align=left |  | 46.98 | |||
| 12 | align=left | align=left | | 47.03 | |||
| 13 | align=left | align=left | | 47.11 | |||
| 14 | align=left | align=left | | 47.16 | |||
| 15 | align=left | align=left | 47.43 | =SB | |||
| 16 | align=left | align=left | | 47.44 | |||
| 17 | align=left | align=left | | 47.75 | |||
| 18 | align=left | align=left |  | 47.99 | |||
| 19 | align=left | align=left |  | 48.98 | |||
| align=left | align=left |  | DNF |
11 July 2013 / 20:00
| Rank | Name | Nationality | Lane | Reaction Time | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 3 | 0.172 | 46.67 | Q | ||
| 2 | align=left | align=left | 2 | 0.157 | 46.67 | Q | |||
| 3 | align=left | align=left | | 4 | 0.186 | 46.98 | |||
| 4 | align=left | align=left | | 6 | 0.217 | 47.16 | |||
| 5 | align=left | align=left | | 5 | 0.178 | 47.44 | |||
| 6 | align=left | align=left | | 7 | 0.202 | 47.99 |
11 July 2013 / 20:08
| Rank | Name | Nationality | Lane | Reaction Time | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 8 | 0.181 | 46.26 | Q PB | |||
| 2 | align=left | align=left | | 4 | 0.189 | 46.35 | Q | ||
| 3 | align=left | align=left | | 3 | 0.152 | 46.57 | q PB | ||
| 4 | align=left | align=left | | 6 | 0.175 | 46.58 | q | ||
| 5 | align=left | align=left | | 7 | 0.189 | 47.03 | |||
| 6 | align=left | align=left | 5 | 0.178 | 47.43 | =SB | |||
| 7 | align=left | align=left | | 2 | 0.212 | 48.98 |
11 July 2013 / 20:16
| Rank | Name | Nationality | Lane | Reaction Time | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 3 | 0.172 | 46.20 | Q | ||
| 2 | align=left | align=left | | 6 | 0.169 | 46.71 | Q | ||
| 3 | align=left | align=left | 7 | 0.168 | 46.97 | ||||
| 4 | align=left | align=left | | 4 | 0.205 | 46.98 | |||
| 5 | align=left | align=left | | 5 | 0.196 | 47.11 | |||
| 6 | align=left | align=left | | 2 | 0.157 | 47.75 | |||
| align=left | align=left | | 8 | 0.213 | DNF |
According to an unofficial count, 20 athletes from 13 countries participated in the event.