| POS | Rank | Heat | BIB | ATHLETE | COUNTRY | RESULTS |
|---|---|---|---|---|---|---|
| 1 | 1 | 1 | USA | United States U20 |
USA |
44.03 Q WJL |
| 2 | 1 | 2 | JAM | Jamaica U20 |
JAM |
44.22 Q |
| 3 | 2 | 1 | BRA | Brazil U20 |
BRA |
44.61 Q SB |
| 4 | 1 | 3 | TTO | Trinidad and Tobago U20 |
TTO |
44.68 Q |
| 5 | 3 | 1 | GER | Germany U20 |
GER |
44.87 q |
| 6 | 2 | 2 | SUI | Switzerland U20 |
SUI |
45.17 Q SB |
| 7 | 4 | 1 | BAH | Bahamas U20 |
BAH |
45.22 q SB |
| 8 | 3 | 2 | NED | Netherlands U20 |
NED |
45.29 |
| 9 | 2 | 3 | JPN | Japan U20 |
JPN |
45.38 Q SB |
| 10 | 3 | 3 | AUS | Australia U20 |
AUS |
45.54 |
| 11 | 4 | 2 | NGR | Nigeria U20 |
NGR |
45.93 |
| 12 | 5 | 1 | RSA | South Africa U20 |
RSA |
46.25 SB |
| 2 | CAN | Canada U20 |
CAN |
DNF | ||
| 3 | POL | Poland U20 |
POL |
DNF | ||
| 3 | GBR | Great Britain & NI U20 |
GBR |
DNF | ||
| 1 | FRA | France U20 |
FRA |
DNF | ||
| 3 | CYP | Cyprus U20 |
CYP |
DQ R170.7 | ||
| 2 | BAR | Barbados U20 |
BAR |
DNS |