The men's 400 metres event at the 2016 IAAF World U20 Championships was held at Zdzisław Krzyszkowiak Stadium on 20, 21 and 22 July.
| Gold | Abdalelah Haroun | |
| Silver | Wilbert London III | |
| Bronze | Karabo Sibanda |
| Standing records prior to the 2016 IAAF World U20 Championships in Athletics | |||||
|---|---|---|---|---|---|
| World Junior Record | 43.87 | Seoul, South Korea | 28 September 1988 | ||
| Championship Record | 44.66 | Santiago, Chile | 20 October 2000 | ||
| World Junior Leading | 44.22 | Gaborone, Botswana | 21 May 2016 | ||
Qualification: First 3 of each heat (Q) and the 6 fastest times (q) qualified for the semifinals.[1]
| Rank | Heat | Name | Nationality | Time | Note | |
|---|---|---|---|---|---|---|
| 1 | 1 | 46.23 | Q, | |||
| 2 | 3 | 46.25 | Q | |||
| 3 | 6 | 46.34 | Q | |||
| 4 | 5 | 46.46 | Q | |||
| 5 | 4 | 46.51 | Q | |||
| 6 | 2 | 46.73 | Q | |||
| 7 | 5 | 46.77 | Q, | |||
| 8 | 2 | 46.78 | Q | |||
| 9 | 6 | 46.83 | Q | |||
| 10 | 4 | 46.83 | Q | |||
| 11 | 4 | 46.91 | Q | |||
| 12 | 6 | 46.96 | Q | |||
| 13 | 3 | 47.09 | Q | |||
| 14 | 6 | 47.11 | q | |||
| 15 | 2 | 47.18 | Q | |||
| 16 | 2 | 47.20 | q | |||
| 17 | 1 | 47.23 | Q | |||
| 18 | 2 | 47.31 | q | |||
| 19 | 3 | 47.32 | Q | |||
| 20 | 1 | 47.39 | Q | |||
| 21 | 6 | 47.62 | q | |||
| 22 | 5 | 47.65 | Q | |||
| 23 | 2 | 47.67 | q | |||
| 24 | 6 | 47.79 | q | |||
| 25 | 1 | 47.82 | ||||
| 26 | 4 | 47.91 | ||||
| 27 | 3 | 47.92 | ||||
| 28 | 1 | 48.01 | ||||
| 29 | 5 | 48.04 | ||||
| 30 | 4 | 48.15 | ||||
| 31 | 5 | 48.36 | ||||
| 32 | 6 | 48.39 | ||||
| 33 | 5 | 48.42 | ||||
| 34 | 3 | 48.60 | ||||
| 35 | 6 | 48.67 | ||||
| 36 | 2 | 49.30 | ||||
| 37 | 1 | 49.54 | ||||
| 38 | 4 | 50.06 | ||||
| 39 | 2 | 50.48 | ||||
| 3 | ||||||
| 1 | ||||||
| 3 | ||||||
| 4 | ||||||
| 5 |
Qualification: First 2 of each heat (Q) and the 2 fastest times (q) qualified for the final.[2]
| Rank | Heat | Name | Nationality | Time | Note | |
|---|---|---|---|---|---|---|
| 1 | 1 | 45.15 | Q | |||
| 2 | 3 | 45.38 | Q | |||
| 3 | 3 | 45.49 | Q | |||
| 4 | 2 | 45.55 | Q | |||
| 5 | 1 | 45.71 | Q | |||
| 6 | 1 | 45.81 | q, | |||
| 7 | 1 | 46.41 | q, | |||
| 8 | 3 | 46.51 | ||||
| 9 | 3 | 46.60 | ||||
| 10 | 1 | 46.61 | ||||
| 11 | 2 | 46.69 | Q | |||
| 12 | 3 | 46.83 | ||||
| 13 | 2 | 47.00 | ||||
| 14 | 1 | 47.09 | ||||
| 15 | 3 | 47.14 | ||||
| 16 | 2 | 47.22 | ||||
| 17 | 1 | 47.26 | ||||
| 18 | 2 | 47.33 | ||||
| 19 | 1 | 47.41 | ||||
| 20 | 3 | 47.46 | ||||
| 21 | 2 | 47.51 | ||||
| 22 | 3 | 47.51 | ||||
| 2 | R163.3(a)[3] | |||||
| 2 |
| Rank | Lane | Name | Nationality | Time | Note | |
|---|---|---|---|---|---|---|
| 6 | 44.81 | |||||
| 7 | 45.27 | |||||
| 5 | 45.45 | |||||
| 4 | 4 | 45.64 | ||||
| 5 | 8 | 46.48 | ||||
| 6 | 2 | 46.50 | ||||
| 7 | 9 | 46.69 | ||||
| 8 | 3 | 47.15 |