# 2010 World Junior Championships in Athletics – Men's 400 metres

The men's 400 metres event at the 2010 World Junior Championships in Athletics was held in Moncton, New Brunswick, Canada, at Moncton Stadium on 20, 21 and 22 July.

## Medalists

| Gold | Kirani James Grenada |
| Silver | Marcell Deák Nagy Hungary |
| Bronze | Errol Nolan United States |

## Results
### Final

22 July
| Rank | Name | Nationality | Time |
| | Kirani James | Grenada | 45.89 |
| | Marcell Deák Nagy | Hungary | 46.09 |
| | Errol Nolan | United States | 46.36 |
| 4 | Marco Kaiser | Germany | 46.79 |
| 5 | Josh Mance | United States | 46.84 |
| 6 | Luguelín Santos | Dominican Republic | 46.90 |
| 7 | Alistair Moona | Canada | 47.38 |
| 8 | Pako Seribe | Botswana | 48.07 |

### Semifinals

21 July

#### Semifinal 1

| Rank | Name | Nationality | Time | Notes |
| 1 | Marcell Deák Nagy | Hungary | 46.23 | Q |
| 2 | Errol Nolan | United States | 46.47 | Q |
| 3 | Pako Seribe | Botswana | 47.02 | q |
| 4 | Omar Longart | Venezuela | 47.25 | |
| 5 | Tobi Ogunmola | Nigeria | 47.43 | |
| 6 | Jacques de Swardt | South Africa | 47.98 | |
| 7 | Jonathan Vilaine | France | 48.08 | |
| 8 | Awad El-Karim Makki | Sudan | 48.55 | |

#### Semifinal 2

| Rank | Name | Nationality | Time | Notes |
| 1 | Kirani James | Grenada | 46.27 | Q |
| 2 | Marco Kaiser | Germany | 46.40 | Q |
| 3 | Luguelín Santos | Dominican Republic | 46.54 | q |
| 4 | Isah Salihu | Nigeria | 47.09 | |
| 5 | Shaun De Jager | South Africa | 47.47 | |
| 6 | Halit Kiliç | Turkey | 47.61 | |
| 7 | Mohamed Abou El-Khair | Egypt | 48.31 | |
| | Park Bong-Go | South Korea | DQ | IAAF rule 163.3 |

#### Semifinal 3

| Rank | Name | Nationality | Time | Notes |
| 1 | Josh Mance | United States | 46.43 | Q |
| 2 | Alistair Moona | Canada | 46.83 | Q |
| 3 | Mateusz Fórmanski | Poland | 47.09 | |
| 4 | Thapelo Ketlogetswe | Botswana | 47.23 | |
| 5 | Deon Lendore | Trinidad and Tobago | 47.49 | |
| 6 | Alex Jordan | New Zealand | 47.65 | |
| 7 | Philipp Kleemann | Germany | 47.86 | |
| 8 | Demar Murray | Jamaica | 48.01 | |

### Heats

20 July

#### Heat 1

| Rank | Name | Nationality | Time | Notes |
| 1 | Mateusz Fórmanski | Poland | 46.75 | Q |
| 2 | Omar Longart | Venezuela | 47.38 | Q |
| 3 | Alex Jordan | New Zealand | 47.50 | Q |
| 4 | Jacques de Swardt | South Africa | 47.50 | q |
| 5 | Demar Murray | Jamaica | 47.62 | q |
| 6 | Philipp Kleemann | Germany | 47.90 | q |
| 7 | Ratutira Narara | Fiji | 48.97 | |
| | Mitchel Davis | Dominica | DQ | IAAF rule 163.3 |

#### Heat 2

| Rank | Name | Nationality | Time | Notes |
| 1 | Marco Kaiser | Germany | 47.06 | Q |
| 2 | Pako Seribe | Botswana | 47.16 | Q |
| 3 | Park Bong-Go | South Korea | 47.46 | Q |
| 4 | Mohamed Abou El-Khair | Egypt | 47.70 | q |
| 5 | Mehmet Güzel | Turkey | 48.07 | |
| 6 | Jermaine Gayle | Jamaica | 48.10 | |
| 7 | Golden Gunde | Malawi | 48.68 | |
| 8 | Mahamoud Athoumani | Comoros | 50.48 | |

#### Heat 3

| Rank | Name | Nationality | Time | Notes |
| 1 | Marcell Deák Nagy | Hungary | 47.31 | Q |
| 2 | Luguelín Santos | Dominican Republic | 47.36 | Q |
| 3 | Awad El-Karim Makki | Sudan | 47.59 | Q |
| 4 | Lim Chan-Ho | South Korea | 47.97 | |
| 5 | Uroš Jovanovic | Slovenia | 48.02 | |
| 6 | Jocelyn Muntaner | French Polynesia | 50.18 | |
| 7 | Michael Rasmijn | Aruba | 51.65 | |

#### Heat 4

| Rank | Name | Nationality | Time | Notes |
| 1 | Josh Mance | United States | 47.29 | Q |
| 2 | Thapelo Ketlogetswe | Botswana | 47.46 | Q |
| 3 | Shaun De Jager | South Africa | 47.48 | Q |
| 4 | Keitaro Sato | Japan | 47.92 | |
| 5 | Tremaine Harris | Canada | 48.34 | |
| 6 | Boniface Mucheru Tumuti | Kenya | 48.85 | |
| 7 | Momodou Kujabi | Gambia | 49.84 | |

#### Heat 5

| Rank | Name | Nationality | Time | Notes |
| 1 | Kirani James | Grenada | 47.12 | Q |
| 2 | Halit Kiliç | Turkey | 47.28 | Q |
| 3 | Deon Lendore | Trinidad and Tobago | 47.33 | Q |
| 4 | Isah Salihu | Nigeria | 47.75 | q |
| 5 | Junki Yanagisawa | Japan | 48.99 | |
| 6 | Mohamed Al-Jumaah | Iraq | 49.81 | |
| 7 | Stephen Newbold | Bahamas | 50.62 | |

#### Heat 6

| Rank | Name | Nationality | Time | Notes |
| 1 | Errol Nolan | United States | 46.67 | Q |
| 2 | Alistair Moona | Canada | 47.22 | Q |
| 3 | Tobi Ogunmola | Nigeria | 47.28 | Q |
| 4 | Jonathan Vilaine | France | 47.54 | q |
| 5 | Kishon Dempster | Trinidad and Tobago | 48.54 | |
| 6 | Scott Burch | New Zealand | 48.63 | |
| | Benjamin Auka Nyasimi | Kenya | DQ | IAAF rule 163.3 |

## Participation

According to an unofficial count, 44 athletes from 31 countries participated in the event.
* Aruba (1)
* Bahamas (1)
* Botswana (2)
* Canada (2)
* Comoros (1)
* Dominica (1)
* Dominican Republic (1)
* Egypt (1)
* Fiji (1)
* France (1)
* French Polynesia (1)
* Gambia (1)
* Germany (2)
* Grenada (1)
* Hungary (1)
* Iraq (1)
* Jamaica (2)
* Japan (2)
* Kenya (2)
* Malawi (1)
* New Zealand (2)
* Nigeria (2)
* Poland (1)
* Slovenia (1)
* South Africa (2)
* South Korea (2)
* Sudan (1)
* Trinidad and Tobago (2)
* Turkey (2)
* United States (2)
* Venezuela (1)