| Date | 29 July 1984 — 8:30 | |
|---|---|---|
| Location | Olympic Swim Stadium, University of Southern California, Los Angeles, California | |
| Format | Fastest 8 advanced to the final round. Places 9-16 advanced to Final B. | |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 5 | Iris Zscherpe |  FRG | 57.31 | ||
| 2 | 3 | Sophie Kamoun |  FRA | 57.49 | ||
| 3 | 4 | Kaori Yanase |  JPN | 58.47 | ||
| 4 | 6 | Teresa Rivera |  MEX | 59.61 | ||
| 5 | 2 | Faten Ghattas |  TUN | 1:02.00 | ||
| 6 | 7 | Anna Doig |  NZL | 1:02.72 | ||
| 7 | 1 | Sharon Pickering |  FIJ | 1:04.25 |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 4 | Annemarie Verstappen |  NED | 56.11 | ||
| 2 | 3 | Silvia Persi |  ITA | 57.62 | ||
| 3 | 5 | Jane Kerr |  CAN | 58.46 | ||
| 4 | 6 | Sofia Dara |  GRE | 59.25 | ||
| 5 | 2 | Carmel Clark | NZL | 1:00.63 | ||
| 6 | 7 | Kathy Wong |  HKG | 1:01.03 | ||
| 7 | 1 | Blanca Morales |  GUA | 1:02.48 |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 4 | Carrie Steinseifer |  USA | 56.46 | ||
| 2 | 5 | Susanne Schuster | FRG | 56.85 | ||
| 3 | 3 | Maarit Sihvonen |  FIN | 58.51 | ||
| 4 | 6 | Marie-Thérèse Armentero |  SUI | 58.73 | ||
| 5 | 7 | Ding Jilian |  CHN | 59.11 | ||
| 6 | 2 | Fenella Ng | HKG | 1:01.82 | ||
| 7 | 1 | Nevine Hafez |  EGY | 1:04.06 |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 3 | Michelle Pearson |  AUS | 56.75 | ||
| 2 | 4 | Conny van Bentum | NED | 56.94 | ||
| 3 | 5 | Pam Rai | CAN | 57.41 | ||
| 4 | 6 | Patricia Kohlmann | MEX | 58.76 | ||
| 5 | 7 | Kim Jin-Suk |  KOR | 1:00.91 | ||
| 6 | 2 | Sandra Crousse |  PER | 1:01.02 | ||
| 7 | 1 | Sherwite Hafez | EGY | 1:02.78 | ||
| 8 | 8 | María Lardizábal |  HON | 1:07.80 |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 4 | June Croft |  GBR | 57.12 | ||
| 2 | 5 | Nikki Fibbens | GBR | 57.80 | ||
| 3 | 3 | Maria Kardum |  SWE | 58.22 | ||
| 4 | 6 | Chikako Nakamori | JPN | 59.00 | ||
| 5 | 2 | Shelley Cramer |  ISV | 1:00.65 | ||
| 6 | 7 | Carol-Ann Heavey |  IRL | 1:01.34 | ||
| 7 | 1 | Christine Jacob |  PHI | 1:02.43 | ||
| 8 | 8 | Karin Slowing | GUA | 1:03.46 |
| Pos | Lane | Competitor | NOC | Time | ||
|---|---|---|---|---|---|---|
| 1 | 4 | Nancy Hogshead | USA | 55.85 | ||
| 2 | 5 | Angela Russell | AUS | 57.30 | ||
| 3 | 3 | Agneta Eriksson | SWE | 58.43 | ||
| 4 | 2 | Grazia Colombo | ITA | 59.43 | ||
| 5 | 7 | Yan Hong | CHN | 1:00.45 | ||
| 6 | 6 | Virginia Sachero |  ARG | 1:00.53 | ||
| 7 | 1 | Helen Chow |  MAS | 1:02.53 | ||
| 8 | 8 | Daniela Galassi |  SMR | 1:06.19 |
