| | Event type
400 metres Hurdles, Boys
| Date | 13 – 16 October 2018 | |
|---|---|---|
| Status | YOG | |
| Location | Athletics Field, Parque Olímpico de la Juventud, Villa Soldati, Buenos Aires | |
| Participants | 16 from 16 countries | |
| Format | Two stages with final results determined by cumulative time. | |
| Pos | Competitor | NOC | Time | |||
|---|---|---|---|---|---|---|
| 1 | Haruto Deguchi |  JPN | 1:42.68 | Gold | ||
| 2 | Dániel Huller |  HUN | 1:43.84 | Silver | ||
| 3 | Mohammed Duhaim Almuawi |  KSA | 1:45.81 | Bronze | ||
| 4 | Martin Fraysse |  FRA | 1:45.85 | |||
| 5 | Pedro Garrido |  ARG | 1:46.78 | |||
| 6 | Shanthamoi Brown |  JAM | 1:47.14 | |||
| 7 | Thomas Throssell |  AUS | 1:47.49 | |||
| 8 | Caio de Almeida |  BRA | 1:47.92 | |||
| 9 | Alejandro Gil |  MEX | 1:49.18 | |||
| 10 | Chang Chun-Yu |  TPE | 1:49.51 | |||
| 11 | Ignacio Sáez |  ESP | 1:50.36 | |||
| 12 | Rami Balti |  TUN | 1:50.62 | |||
| 13 | Matthew Thompson |  BAH | 1:50.81 | |||
| 14 | Mauricio Lizano |  CRC | 1:51.90 | |||
| Lindukuhle Gora |  RSA | – | ||||
| Eloi Kiendrebeogo |  BUR | – |