We investigated the utility of the collagen gel droplet culture drug-sensitivity test (CD-DST) for predicting the response of gynecological cancers to chemotherapy. Eighty-three cancer patients were enrolled in this study: 26 ovarian, 29 cervical and 31 endometrial cancers. The CD-DST was performed at various concentrations of drugs. We calculated the T/C ratio, where T is the total volume of the treated culture and C is the total volume of the control culture, and a T/C ratio of 50% or less was defined as sensitive in vitro. The efficacy rate (%) was defined as the number of cultures with a T/C ratio of 50% or less, divided by the total number of evaluable cultures. True-positive cases were defined as clinical responders (complete+partial responses) and true-negative cases were defined as clinical non-responders. The overall tumor evaluation rate was found to be 79.1%. The appropriate drug concentrations were selected as 1.0 μg/ml for cisplatin, 20.0 μg/ml for carboplatin, 1.0 μg/ml for paclitaxel and 0.1 μg/ml for docetaxel by the linear regression equations. The in vitro sensitivity for each drug showed a significant correlation with clinical response rates (r=0.592, p=0021). We therefore conclude that the CD-DST can be used to predict the response to anti-cancer drugs, and may also provide important information by contributing to the development of new chemotherapy regimens.