Although considerable clinical data are available to guide treatment decisions for patients with ovarian epithelial malignancies, therapy for the rare malignant mixed mesodermal (mullerian) tumor (MMMT) of the ovary is poorly studied. Ten untreated patients diagnosed with primary ovarian MMMT were managed with cis-platinum-based combination chemotherapy from 1980 to 1985. Six of the 10 patients were stage III suboptimal with evaluable residual disease; 4 of these 6 had CRs with a median duration of response of 13 months. The remaining 2 patients had PRs, of 2 and 11 months duration. Four patients had stage III optimal disease; 1 progressed at 7 months, 1 progressed at 16 months and the other 2 patients have no clinical evidence of disease at 12+ and 22+ months. Despite impressive initial response rates, survival overall was poor, with a median survival for all 10 patients of 16+ months.