| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 985 | Amy Mbacke Thiam |  SEN | 50.78 Q | 0.315 | 
| 2 | 934 | Svetlana Pospelova |  RUS | 50.84 Q | 0.152 | 
| 3 | 403 | Lee McConnell |  GBR | 51.06 q SB | 0.240 | 
| 4 | 1155 | Sanya Richards-Ross |  USA | 51.32 | 0.229 | 
| 5 | 777 | Olabisi Afolabi |  NGR | 51.38 | 0.182 | 
| 6 | 609 | Ronetta Smith |  JAM | 51.39 | 0.132 | 
| 7 | 895 | Heide Seyerling |  RSA | 51.89 | 0.185 | 
| 8 | 500 | Hazel Regis-Buckels |  GRN | 51.95 | 0.192 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 69 | Tonique Williams-Darling |  BAH | 50.43 Q | 0.161 | 
| 2 | 593 | Lorraine Fenton |  JAM | 50.45 Q | 0.176 | 
| 3 | 945 | Olesya Zykina |  RUS | 50.96 q | 0.152 | 
| 4 | 1168 | Demetria Washington |  USA | 51.31 | 0.215 | 
| 5 | 1162 | Deedee Trotter |  USA | 51.68 | 0.155 | 
| 6 | 838 | Grazyna Prokopek |  POL | 51.89 | 0.250 | 
| 7 | 332 | Makelesi Batimala |  FIJ | 52.27 | 0.168 | 
| 8 | 1109 | Antonina Yefremova |  UKR | 53.19 | 0.182 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 726 | Ana Guevara |  MEX | 50.68 Q | 0.194 | 
| 2 | 930 | Natalya Nazarova |  RUS | 50.92 Q | 0.190 | 
| 3 | 196 | Mireille Nguimgo |  CMR | 51.19 | 0.180 | 
| 4 | 105 | Sviatlana Usovich |  BLR | 51.46 | 0.184 | 
| 5 | 608 | Sandie Richards |  JAM | 51.80 SB | 0.223 | 
| 6 | 61 | Christine Amertil |  BAH | 51.85 | 0.160 | 
| 7 | 556 | Anna Tkach |  ISR | 52.25 | 0.214 | 
| 8 | 547 | Karen Shinkins |  IRL | 52.74 | 0.166 |