The men's 400 metres at the 2010 African Championships in Athletics were held on July 28–30.
| width=200 bgcolor=gold | Gold | width=200 bgcolor=silver | Silver | width=250 bgcolor=CC9966 | Bronze |
Mohamed Khawaja Libya | Rabah Yousif | Gary Kikaya |
Qualification: First 4 of each heat (Q) and the next 4 fastest (q) qualified for the semifinals.
| Rank | Heat | Name | Nationality | Time | Notes | |
|---|---|---|---|---|---|---|
| 1 | 5 | 46.01 | Q | |||
| 2 | 5 | 46.07 | Q | |||
| 3 | 2 | 46.11 | Q | |||
| 4 | 3 | 46.36 | Q | |||
| 5 | 1 | 46.39 | Q | |||
| 6 | 4 | 46.54 | Q | |||
| 7 | 5 | 46.65 | Q | |||
| 8 | 3 | 46.66 | Q | |||
| 9 | 4 | 46.72 | Q | |||
| 10 | 1 | 46.78 | Q | |||
| 11 | 3 | 46.78 | Q | |||
| 12 | 3 | 46.94 | Q | |||
| 13 | 1 | 46.97 | Q | |||
| 14 | 4 | 47.03 | Q | |||
| 15 | 4 | 47.16 | Q | |||
| 16 | 2 | 47.16 | Q | |||
| 17 | 1 | 47.45 | Q | |||
| 18 | 3 | 47.88 | q | |||
| 19 | 5 | 48.13 | Q | |||
| 20 | 3 | 48.42 | q | |||
| 21 | 2 | 48.55 | Q | |||
| 22 | 5 | 48.65 | q | |||
| 23 | 3 | 49.06 | q | |||
| 24 | 2 | 49.07 | Q | |||
| 25 | 4 | 49.54 | ||||
| 26 | 2 | 49.97 | ||||
| 27 | 2 | 50.16 | SB | |||
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Qualification: First 2 of each semifinal (Q) and the next 2 fastest (q) qualified for the final.
| Rank | Heat | Name | Nationality | Time | Notes | |
|---|---|---|---|---|---|---|
| 1 | 3 | 45.42 | Q, SB | |||
| 2 | 2 | 45.55 | Q | |||
| 3 | 2 | 45.69 | Q, SB | |||
| 4 | 1 | 45.82 | Q | |||
| 5 | 3 | 45.83 | Q | |||
| 6 | 1 | 45.97 | Q | |||
| 7 | 2 | 46.12 | q | |||
| 8 | 1 | 46.21 | q | |||
| 9 | 1 | 46.26 | PB | |||
| 10 | 2 | 46.41 | ||||
| 11 | 1 | 46.45 | ||||
| 12 | 3 | 46.55 | ||||
| 13 | 3 | 46.79 | ||||
| 14 | 3 | 46.92 | ||||
| 15 | 2 | 46.98 | ||||
| 16 | 3 | 47.32 | ||||
| 17 | 1 | 47.44 | ||||
| 18 | 1 | 47.95 | ||||
| 19 | 1 | 48.20 | ||||
| 20 | 3 | 48.39 | ||||
| 21 | 2 | 48.48 | ||||
| 22 | 2 | 49.04 | ||||
| 23 | 3 | 49.27 | ||||
| 2 |
| Rank | Lane | Name | Nationality | Time | Notes | |
|---|---|---|---|---|---|---|
| 3 | 44.98 | NR | ||||
| 5 | 45.18 | |||||
| 6 | 45.28 | |||||
| 4 | 4 | 45.28 | SB | |||
| 5 | 2 | 45.50 | PB | |||
| 6 | 7 | 45.62 | ||||
| 7 | 1 | 45.93 | ||||
| 8 | 8 | 47.14 |