2008 IAAF World Indoor Championships – Men's 400 metres Semifinals Semifinals

| Heat | Lane | Name_ | Country | Mark | React |
|---|---|---|---|---|---|
| 1 | 5 | Tyler Christopher | Canada | 46.57 | 0.253 |
| 1 | 6 | Johan Wissman | Sweden | 46.86 | 0.242 |
| 1 | 3 | Sean Wroe | Australia | 47.13 PB | 0.257 |
| 1 | 2 | Denis Alekseyev | Russia | 47.18 | 0.292 |
| 1 | 4 | California Molefe | Botswana | 47.74 | 0.342 |
| 1 | 1 | David Neville | United States | 48.18 | 0.294 |
| 2 | 4 | Chris Brown | Bahamas | 46.68 | 0.254 |
| 2 | 5 | Nery Brenes | Costa Rica | 46.85 | 0.298 |
| 2 | 6 | Maksim Dyldin | Russia | 46.92 | 0.257 |
| 2 | 3 | Chris Lloyd | Dominica | 46.92 | 0.189 |
| 2 | 2 | Richard Buck | United Kingdom | 47.60 | 0.232 |
| 2 | 1 | DeWayne Barrett | Jamaica | 48.41 | 0.242 |