2018 IAAF World U20 Championships – Men's 400 metres hurdles
The men's 400 metres hurdles at the 2018 IAAF World U20 Championships will be held at Ratina Stadium on 12, 13 and 14 July.Records
Results
Heats
Qualification: First 3 of each heat and the 6 fastest times qualified for the semifinals.
| Rank | Heat | Name | Nationality | Time | Note |
| 1 | 4 | Moitalel Mpoke Naadokila | KEN | 50.87 | Q, |
| 2 | 3 | Rasheeme Griffith | BAR | 51.02 | Q, |
| 3 | 4 | Alison dos Santos | BRA | 51.08 | Q |
| 4 | 2 | Alastair Chalmers | GBR | 51.16 | Q |
| 5 | 5 | Sokwakhana Zazini | RSA | 51.21 | Q |
| 6 | 5 | Alex Knibbs | GBR | 51.29 | Q |
| 7 | 4 | Carl Bengtström | SWE | 51.35 | Q |
| 8 | 4 | Ierotheos Dritsas | GRE | 51.39 | q, |
| 9 | 6 | Malik James-King | JAM | 51.54 | Q |
| 10 | 2 | Alessandro Sibilio | ITA | 51.59 | Q SB |
| 11 | 2 | Julien Bonvin | SUI | 51.64 | Q, |
| 12 | 3 | Leonardo Ledgister | JAM | 51.65 | Q |
| 13 | 3 | Quivell Jordan | USA | 51.75 | Q |
| 14 | 3 | Aleix Porras | ESP | 51.83 | q |
| 15 | 2 | Ramsey Angela | NED | 51.95 | q |
| 16 | 4 | Nathan Fergusson | BAR | 52.02 | q, |
| 17 | 6 | Yusuke Shirao | JPN | 52.09 | Q |
| 18 | 1 | Cory Poole | USA | 52.12 | Q |
| 19 | 5 | Jesús David Delgado | ESP | 52.13 | Q |
| 20 | 4 | Mahdi Pirjahan | IRI | 52.18 | q |
| 21 | 3 | Ismail Manyani | MAR | 52.24 | q |
| 22 | 1 | Bassem Hemeida | QAT | 52.35 | Q |
| 23 | 1 | Lourens Steenekamp | RSA | 52.35 | Q |
| 24 | 6 | Boaz Madeus | HAI | 52.38 | Q |
| 25 | 1 | Hayata Goto | JPN | 52.48 | |
| 26 | 5 | Gadisa Bayu | ETH | 52.59 | |
| 27 | 6 | Samuele Licata | ITA | 52.60 | |
| 28 | 5 | Emil Agyekum | GER | 52.70 | |
| 29 | 1 | Karl Erik Nazarov | EST | 52.80 | |
| 30 | 6 | Fu Jiahao | CHN | 52.82 | |
| 31 | 2 | James Mucheru | KEN | 52.88 | |
| 32 | 3 | Harvey Murrant | AUS | 53.02 | |
| 33 | 2 | Dániel Huller | HUN | 53.13 | |
| 34 | 3 | Vesa Kittilä | FIN | 53.21 | |
| 35 | 5 | Damián Moretta | ARG | 53.43 | |
| 36 | 5 | Fahd Benammar | TUN | 53.71 | |
| 37 | 4 | Nathaniel St. Romain | CAN | 53.85 | |
| 38 | 1 | Anton Bertilsson | SWE | 54.82 | |
| 39 | 1 | Branson Rolle | BAH | 1:08.85 | |
| 2 | Sergio Armando Esquivel | MEX | | - |
| 6 | Norman Mukwada | ZIM | | |
| 6 | Justus Ringel | GER | | |
Semifinals
Qualification: First 2 of each heat and the 2 fastest times qualified for the final.
| Rank | Heat | Name | Nationality | Time | Note |
| 1 | 3 | Sokwakhana Zazini | RSA | 49.43 | Q |
| 2 | 3 | Alastair Chalmers | GBR | 50.11 | Q, |
| 3 | 3 | Leonardo Ledgister | JAM | 50.13 | q, |
| 4 | 2 | Malik James-King | JAM | 50.34 | Q |
| 5 | 3 | Alessandro Sibilio | ITA | 50.73 | q, |
| 6 | 3 | Quivell Jordan | USA | 50.86 | |
| 7 | 1 | Alison dos Santos | BRA | 50.90 | Q |
| 8 | 2 | Mahdi Pirjahan | IRI | 50.98 | Q, |
| 9 | 2 | Alex Knibbs | GBR | 50.99 | |
| 10 | 2 | Rasheeme Griffith | BAR | 51.02 | |
| 11 | 1 | Bassem Hemeida | QAT | 51.14 | Q |
| 12 | 2 | Yusuke Shirao | JPN | 51.21 | |
| 13 | 2 | Lourens Steenekamp | RSA | 51.26 | |
| 14 | 1 | Cory Poole | USA | 51.27 | |
| 15 | 1 | Carl Bengtström | SWE | 51.55 | |
| 16 | 2 | Julien Bonvin | SUI | 51.83 | |
| 17 | 1 | Moitalel Mpoke Naadokila | KEN | 51.94 | |
| 18 | 3 | Ramsey Angela | NED | 51.99 | |
| 19 | 3 | Jesús David Delgado | ESP | 52.18 | |
| 20 | 1 | Ierotheos Dritsas | GRE | 52.38 | |
| 21 | 1 | Boaz Madeus | HAI | 54.45 | |
| 22 | 3 | Nathan Fergusson | BAR | 54.58 | |
| 1 | Ismail Manyani | MAR | | |
| 2 | Aleix Porras | ESP | | |
Final
| Rank | Lane | Name | Nationality | Time | Note |
| 4 | Sokwakhana Zazini | RSA | 49.42 | |
| 7 | Bassem Hemeida | QAT | 49.59 | |
| 6 | Alison dos Santos | BRA | 49.78 | |
| 4 | 2 | Leonardo Ledgister | JAM | 49.93 | |
| 5 | 3 | Malik James-King | JAM | 50.25 | |
| 6 | 5 | Alastair Chalmers | GBR | 50.27 | |
| 7 | 8 | Mahdi Pirjahan | IRI | 51.15 | |
| 8 | 1 | Alessandro Sibilio | ITA | 52.38 | |
