The women's 400 metres event at the 1992 World Junior Championships in Athletics was held in Seoul, Korea, at Olympic Stadium on 16, 17 and 18 September.
| Gold | Maria Magdalena Nedelcu | |
| Silver | Claudine Williams | |
| Bronze | Ionela Tîrlea |
18 September
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| align=left | align=left | | 51.84 | ||||
| align=left | align=left | | 52.03 | ||||
| align=left | align=left | | 52.13 | ||||
| 4 | align=left | align=left |  | 52.98 | |||
| 5 | align=left | align=left | 53.39 | ||||
| 6 | align=left | align=left |  | 53.45 | |||
| 7 | align=left | align=left | 53.73 | ||||
| 8 | align=left | align=left |  | 54.30 |
17 September
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 52.88 | Q | ||
| 2 | align=left | align=left | | 52.90 | Q | ||
| 3 | align=left | align=left | 53.44 | Q | |||
| 4 | align=left | align=left | | 54.26 | Q | ||
| 5 | align=left | align=left |  | 54.27 | |||
| 6 | align=left | align=left |  | 55.27 | |||
| 7 | align=left | align=left | 55.55 | ||||
| align=left | align=left | DNS |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 52.87 | Q | ||
| 2 | align=left | align=left | | 53.26 | Q | ||
| 3 | align=left | align=left | 53.58 | Q | |||
| 4 | align=left | align=left | | 53.81 | Q | ||
| 5 | align=left | align=left | | 53.91 | |||
| 6 | align=left | align=left | 54.69 | ||||
| 7 | align=left | align=left | | 55.17 | |||
| 8 | align=left | align=left |  | 55.91 |
16 September
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 53.20 | Q | ||
| 2 | align=left | align=left | | 54.55 | Q | ||
| 3 | align=left | align=left | 54.71 | Q | |||
| 4 | align=left | align=left | | 54.91 | q | ||
| 5 | align=left | align=left | | 55.44 | q | ||
| 6 | align=left | align=left | | 55.61 |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 53.49 | Q | ||
| 2 | align=left | align=left | | 53.92 | Q | ||
| 3 | align=left | align=left | 55.03 | Q | |||
| 4 | align=left | align=left |  | 55.85 | |||
| 5 | align=left | align=left | | 56.07 | |||
| align=left | align=left | DNF |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 53.53 | Q | ||
| 2 | align=left | align=left | | 54.50 | Q | ||
| 3 | align=left | align=left | 54.83 | Q | |||
| 4 | align=left | align=left | 55.45 | q | |||
| 5 | align=left | align=left | 55.94 | ||||
| 6 | align=left | align=left |  | 56.10 |
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | | 53.65 | Q | ||
| 2 | align=left | align=left | | 54.19 | Q | ||
| 3 | align=left | align=left | | 54.78 | Q | ||
| 4 | align=left | align=left | 54.91 | q | |||
| 5 | align=left | align=left | 55.61 | ||||
| 6 | align=left | align=left | | 56.06 |
According to an unofficial count, 24 athletes from 17 countries participated in the event.