| Women 100m Butterfly Swimming III World Championship 1978 West Berlin - Wednesday, 23rd August - Gold Medal: Joan Pennington, United States | 
| Final |   | time |   | gap | L | ag | 50m |  | 1. Joan Pennington |   United States | 1:00.20 | CR |   | 5 | 18 | 28.37s  |  | 2. Andrea Pollack |   East Germany | 1:00.26 |   | +0.06 | 4 | 17 | 28.41s  |  | 3. Wendy Quirk |   Canada | 1:01.82 |   | +1.62 | 3 | 19 | 29.43s  |  | 4. Betsy Rapp |   United States | 1:02.29 |   | +2.09 | 8 | _ | 29.48s  |  | 5. Karin Seick |   West Germany | 1:02.71 |   | +2.51 | 6 | 16 | 29.45s  |  | 6. Susan Sloan |   Canada | 1:02.74 |   | +2.54 | 1 | 20 | 29.78s  |  | 6. Ann Osgerby |   Great Britain | 1:02.74 | NR | +2.54 | 7 | 15 | 30.00s  |  | 8. Enith Brigitha |   Netherlands | 1:02.78 | NR | +2.58 | 2 | 23 | 29.62s  |   
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| World Record: Andrea Pollack, East Germany 59.46s (29.39s) |  | Championship Record: Kornelia Ender, East Germany 1:01.24 (28.58) 1975 |   
|
 Heats - Wednesday, 23rd August |  | Best 8 times advanced to Final>.  |   
| Heat 5 |   | time |   | gap | L | ag | Rk |  | 1. Andrea Pollack |   East Germany | 1:00.86 | CR |   | - | 17 | 1. |  | 6. Ann Osgerby |   Great Britain | 1:02.90 |   | +2.04s | - | 15 | 2. |  | 7. Susan Sloan |   Canada | 1:02.97 |   | +2.11s | - | 20 | 3. |  | 9. Cinzia Savi-Scarponi |   Italy | 1:03.16 |   | +2.30s | - | 14 | 4. |  | 22.Miriam Hopkins |   Ireland | 1:05.95 |   | +5.09s | - | 17 | 5. |   
| Heat 4 |   | time |   | gap | L | ag | Rk |  | 2. Joan Pennington |   United States | 1:01.35 |   | +0.49s | - | 18 | 1. |  | 5. Enith Brigitha |   Netherlands | 1:02.89 |   | +2.03s | - | 23 | 2. |  | 13.Linda Hanel |   Australia | 1:03.66 |   | +2.80s | - | 16 | 3. |  | 15.Yasue Hatsuda |   Japan | 1:04.35 |   | +3.49s | - | 18 | 4. |  | 16.Cristina Quintarelli |   Italy | 1:04.55 |   | +3.69s | - | 14 | 5. |   
| Heat 3 |   | time |   | gap | L | ag | Rk |  | 8. Betsy Rapp |   United States | 1:03.04 |   | +2.18s | - | _ | 1. |  | 14.Lena De Val |   Sweden | 1:03.70 |   | +2.84s | - | _ | 2. |  | 20.Sue Jenner |   Great Britain | 1:04.87 |   | +4.01s | - | 18 | 3. |   
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| Heat 2 |   | time |   | gap | L | ag | Rk |  | 4. Karin Seick |   West Germany | 1:02.63 | NR | +1.77s | - | 16 | 1. |  | 18.Agneta Martensson |   Sweden | 1:04.69 |   | +3.83s | - | 17 | 2. |   
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| Heat 1 |   | time |   | gap | L | ag | Rk |  | 3. Wendy Quirk |   Canada | 1:02.45 |   | +1.59s | - | 19 | 1. |  | 10.Maria Paris |   Costa Rica | 1:03.37 |   | +2.51s | - | 17 | 2. |  | 11.Ineke Ran |   Netherlands | 1:03.49 |   | +2.63s | - | 16 | 3. |  | 12.Penny McCarthy |   New Zealand | 1:03.64 |   | +2.78s | - | _ | 4. |   
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| Heat - |   | time |   | gap | L | ag | Rk  |  | 17.Shelley Katherine Cramer |   US Virgin Islands | 1:04.61 | NR | +3.75s | - | 16 |   |  | 19.Barbara Qellrtch |   West Germany | 1:04.82 |   | +3.96s | - | _ |   |  | 21.Alia Grichenkova |   Soviet Union | 1:05.67 |   | +4.81s | - | 29 |   |  | 23.Martine Verbreyt |   Belgium | 1:05.96 |   | +5.10s | - | _ |   |  | 24.Valeriya Tarbeyeva |   Soviet Union | 1:06.57 |   | +5.71s | - | _ |   |  | 25.Rosanna Juncos |   Argentina | 1:06.50 |   | +5.64s | - | 20 |   |  | 26.Renata Damiecka |   Poland | 1:07.68 | NR | +6.82s | - | _ |   |  | 27.Yue-Yun Hsu |   Taiwan | 1:07.72 |   | +6.86s | - | 20 |   |  | 28.Yasmine Kummer |   Luxembourg | 1:07.83 |   | +6.97s | - | _ |   |  | 29.Porunn Alfredsdottir |   Iceland | 1:08.42 |   | +7.56s | - | 17 |   |  | 30.Wen-Hsuen Kiang |   Taiwan | 1:09.32 |   | +8.46s | - | _ |   |  | 31.Ratchaneewan Bulakul |   Thailand | 1:09.55 | NR | +8.69s | - | 15 |   |  | 32.Sumatana Pingkatswan |   Thailand | 1:12.01 |   | +11.15s | - | _ |   |  | -. Christiane Knacke |   East Germany | DNF |   | - | - | 16 |   |  | -. Tracey Wickham |   Australia | DNS |   | - | - | 15 |   |   
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