2012 World Junior Championships in Athletics – Men's 400 metres hurdles
The men's 400 metres hurdles at the 2012 World Junior Championships in Athletics was held at the Estadi Olímpic Lluís Companys on 11–13 July.
Medalists
Records
, the existing world junior and championship records were as follows.Results
Heats
Qualification: first 3 of each heat plus the 3 fastest times qualified| Rank | Heat | Lane | Name | Nationality | Time | Note |
| 1 | 7 | 3 | Gregory Coleman | 50.95 | Q, PB | |
| 2 | 1 | 5 | Mitja Lindic | 51.16 | Q, PB | |
| 3 | 4 | 9 | Takahiro Matsumoto | 51.26 | Q, SB | |
| 4 | 3 | 5 | Ibrahim Mohammed Saleh | 51.36 | Q | |
| 5 | 4 | 4 | Javarn Gallimore | 51.40 | Q | |
| 6 | 7 | 9 | Shavon Barnes | 51.52 | Q | |
| 7 | 1 | 6 | Oskari Mörö | 51.65 | Q | |
| 8 | 6 | 9 | Shota Madokoro | 51.67 | Q | |
| 9 | 3 | 9 | Riadh Sayeh | 51.68 | Q, PB | |
| 10 | 1 | 3 | Felix Franz | 51.78 | Q | |
| 11 | 5 | 6 | Eric Futch | 51.82 | Q | |
| 12 | 7 | 8 | Max Scheible | 51.82 | Q, SB | |
| 13 | 6 | 6 | Gamal Abdelnasir Abubaker | 51.93 | Q, PB | |
| 14 | 3 | 4 | Durgesh Kumar | 51.99 | Q | |
| 15 | 2 | 8 | Brandon Benjamin | 52.01 | Q | |
| 16 | 3 | 6 | Máté Koroknai | 52.16 | q, SB | |
| 17 | 6 | 3 | José Fernando Martínez | 52.21 | Q | |
| 18 | 2 | 9 | Timofey Chalyy | 52.27 | Q | |
| 19 | 5 | 8 | Kion Joseph | 52.29 | Q | |
| 20 | 5 | 7 | Francis Wanguo Mutunga | 52.31 | Q | |
| 21 | 6 | 4 | Marius Bakken Støle | 52.37 | q | |
| 22 | 5 | 9 | Ben Kiely | 52.39 | q, PB | |
| 23 | 1 | 8 | Wesley Diego Martins | 52.41 | ||
| 24 | 2 | 2 | Thomas Kain | 52.42 | Q | |
| 25 | 4 | 8 | William Mbevi Mutunga | 52.44 | Q | |
| 26 | 1 | 7 | Tramaine Maloney | 52.56 | ||
| 27 | 3 | 7 | Oleg Mironov | 52.56 | ||
| 28 | 5 | 5 | Ioánnis Loulás | 52.61 | ||
| 29 | 2 | 3 | Joni Vainio-Kaila | 52.71 | PB | |
| 30 | 7 | 2 | Andri Aguirre | 52.71 | ||
| 31 | 1 | 9 | Paolo Spezzati | 52.73 | PB | |
| 32 | 4 | 6 | Ramfis Vega | 52.77 | ||
| 33 | 7 | 5 | Gatkuath Chol | 52.78 | ||
| 34 | 4 | 2 | Erick Armando Valverde | 52.85 | ||
| 35 | 7 | 6 | Mustafa Ammar Shaheen | 52.94 | ||
| 36 | 2 | 4 | Taariq Solomons | 52.95 | ||
| 37 | 7 | 7 | Enrico Tirel | 53.00 | PB | |
| 38 | 4 | 5 | Marcin Młynarczyk | 53.06 | ||
| 39 | 3 | 8 | Dmytro Bezpamyatnyy | 53.11 | ||
| 40 | 3 | 3 | Phil Simms | 53.26 | ||
| 41 | 1 | 4 | Ju Sang-min | 53.29 | ||
| 42 | 2 | 6 | Markus Loftås | 53.29 | SB | |
| 43 | 6 | 5 | Alfredo Sepúlveda | 53.43 | ||
| 44 | 2 | 5 | Gerald Drummond | 53.46 | ||
| 45 | 2 | 7 | Sergio Fernández | 53.50 | ||
| 46 | 5 | 3 | Enrique González | 53.74 | ||
| 47 | 4 | 3 | Ali Khamis Khamis | 53.90 | ||
| 48 | 7 | 4 | Yahya Ibrahim Barnawi | 54.03 | SB | |
| 49 | 6 | 8 | Tamás Kovári | 54.13 | ||
| 50 | 4 | 7 | Christopher Green | 54.51 | ||
| 51 | 5 | 4 | Alejandro Díaz | 55.65 | ||
| 52 | 6 | 7 | Bernardus Pretorius | 57.21 |
Semi-Final
Qualification: The first 2 of each heat and the 2 fastest times qualified| Rank | Heat | Lane | Name | Nationality | Time | Note |
| 1 | 2 | 6 | Javarn Gallimore | 50.45 | Q, WJL | |
| 2 | 1 | 9 | Felix Franz | 50.66 | Q | |
| 3 | 1 | 4 | Takahiro Matsumoto | 50.76 | Q, PB | |
| 4 | 3 | 6 | Eric Futch | 50.77 | Q | |
| 5 | 2 | 9 | Timofey Chalyy | 50.80 | Q, PB | |
| 6 | 3 | 5 | Mitja Lindic | 50.81 | Q, PB | |
| 7 | 1 | 7 | Oskari Mörö | 50.89 | q, PB | |
| 8 | 1 | 6 | Ibrahim Mohammed Saleh | 51.11 | q, PB | |
| 9 | 2 | 5 | Gregory Coleman | 51.12 | ||
| 10 | 3 | 7 | Shota Madokoro | 51.15 | ||
| 11 | 1 | 5 | Shavon Barnes | 51.18 | ||
| 12 | 3 | 4 | Riadh Sayeh | 51.36 | NJ | |
| 13 | 3 | 9 | Max Scheible | 51.43 | PB | |
| 14 | 3 | 8 | Kion Joseph | 51.51 | PB | |
| 14 | 3 | 2 | Thomas Kain | 51.51 | PB | |
| 16 | 1 | 8 | Durgesh Kumar | 51.52 | ||
| 17 | 2 | 3 | Francis Wanguo Mutunga | 51.65 | ||
| 18 | 1 | 2 | William Mbevi Mutunga | 51.70 | ||
| 19 | 2 | 7 | Brandon Benjamin | 51.93 | ||
| 20 | 3 | 3 | Marius Bakken Støle | 52.33 | ||
| 21 | 1 | 3 | Máté Koroknai | 52.51 | ||
| 22 | 2 | 8 | José Fernando Martínez | 52.67 | ||
| 23 | 2 | 2 | Ben Kiely | 53.06 | ||
| – | 2 | 4 | Gamal Abdelnasir Abubaker | DNF |