| Final | time | | 1. Jean Patton |  United States | 25.3s | | 2. Nell Jackson | United States | 25.7s | | 3. Adriana Millard Pacheco |  Chile | 26.1s | | 4. Beatriz Kretschmer de Buccicardi | Chile | 26.7s | | 5. Cecilia Navarrete |  Colombia | 26.9s | | 6. Dolores Dwyer | United States | 27.7s |
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| Heat | time | | 1. Jean Patton | United States | 25.7s | | 2. Adriana Millard Pacheco | Chile | 26.4s | | 3. Dolores Dwyer | United States | 26.6s | | 4. Teresa Carvajal |  Argentina | 26.7s | | 5. Alejandrina Correa | Colombia | 27.8s | | -. Deyse Jurdelina de Castro |  Brazil | DNF |
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| Heat | time | | 1. Nell Jackson | United States | 26.3s | | 2. Beatriz Kretschmer de Buccicardi | Chile | 26.7s | | 3. Cecilia Navarrete | Colombia | 27.0s | | 4. Oldemia Bargiela de Martin | Argentina | 27.1s | | 5. Cora Pascasio | Argentina | 27.8s |
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| Heat 1 | time | | 1. Jean Patton | United States | 26.2 | | 2. Teresa Carvajal | Argentina | 27.2 | | 3. Alejandrina Correa | Colombia | 28.0 | | -. Graviola Ewing |  Guatemala | DSQ | | -. Carmen Matos Garcia |  Ecuador | DNR |
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| Heat 2 | time | | 1. Dolores Dwyer | United States | 27.3s | | 2. Deyse Jurdelina de Castro | Brazil | 28.0s | | 3. Adriana Millard Pacheco | Chile | 28.0s | | -. Leonor Estevez Bucheli | Ecuador | DNR |
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| Heat 3 | time | | 1. Beatriz Kretschmer de Buccicardi | Chile | 27.1s | | 2. Cora Pascasio | Argentina | 27.4s | | -. Helena Cardoso de Menezes | Brazil | DNR | | -. Julia Sánchez Deze |  Peru | DNR |
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| Heat 4 | time | | 1. Nell Jackson | United States | 26.5s | | 2. Oldemia Bargiela de Martin | Argentina | 27.3s | | 3. Cecilia Navarrete | Colombia | 27.5s | | -. Aida Mawyn Cedeno | Ecuador | DNR |
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