The women's 400 metres event at the 2005 European Athletics U23 Championships was held in Erfurt, Germany, at Steigerwaldstadion on 15 and 16 July.
| Gold | Olga Zaytseva | |
| Silver | Christine Ohuruogu | |
| Bronze | Yelena Migunova |
16 July
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| align=left | align=left | | 50.72 | CR | |||
| align=left | align=left | | 50.73 | ||||
| align=left | align=left | | 51.59 | ||||
| 4 | align=left | align=left | | 52.24 | |||
| 5 | align=left | align=left |  | 52.44 | |||
| 6 | align=left | align=left | | 52.84 | |||
| 7 | align=left | align=left |  | 52.87 | |||
| 8 | align=left | align=left |  | 52.93 |
15 July
Qualified: first 2 in each heat and 2 best to the Final
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 51.69 | Q | ||
| 2 | align=left | align=left | | 51.85 | Q | ||
| 3 | align=left | align=left | | 52.74 | q | ||
| 4 | align=left | align=left | | 52.88 | q | ||
| 5 | align=left | align=left |  | 53.66 | |||
| 6 | align=left | align=left | 53.93 | ||||
| 7 | align=left | align=left |  | 54.94 |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 51.82 | Q | ||
| 2 | align=left | align=left | | 52.85 | Q | ||
| 3 | align=left | align=left | | 53.22 | |||
| 4 | align=left | align=left |  | 54.54 | |||
| 5 | align=left | align=left |  | 55.66 |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 52.53 | Q | ||
| 2 | align=left | align=left | | 52.70 | Q | ||
| 3 | align=left | align=left | | 53.43 | |||
| 4 | align=left | align=left | | 53.57 | |||
| 5 | align=left | align=left | | 53.78 | |||
| 6 | align=left | align=left |  | 54.80 |
According to an unofficial count, 18 athletes from 11 countries participated in the event.
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