OBJECTIVE To characterize the clinical course of patients diagnosed with ovarian malignant mixed müllerian tumors treated with platinum-based chemotherapy. METHODS Thirty-six patients received this treatment at The University of Texas M. D. Anderson Cancer Center in the period 1979-1993. The mean age was 59 years. Stage distribution was as follows: stage IA, one (3%) patient; stage IIIB, two (5.5%); stage IIIC, 21 (58%); and stage IV, two (5.5%). Ten (28%) patients were unstaged. Chemotherapy regimens included cisplatin, doxorubicin, and cyclophosphamide in 16 patients; cisplatin-ifosfamide in five; cisplatin-cyclophosphamide in four; carboplatinum in three; cisplatin-doxorubicin in three; and various other combinations in the remaining five. RESULTS Of 16 patients evaluated for clinical response, seven (44%) had a complete response and four (25%) had a partial response, for a total clinical response rate of 69%. Nine patients were evaluated for surgical response: five (56%) had a complete response and one (11%) had a partial response, for a total surgical response rate of 67%. The median survival for the cohort was 18 months. At the time of this analysis, five (14%) patients were alive and disease-free, 25 (69%) had died of disease, five (14%) were alive with disease, and one had been lost to follow-up. CONCLUSIONS This study suggests that the clinical course of patients with ovarian malignant mixed müllerian tumors treated with platinum-based chemotherapy is similar to the clinical course experienced by patients with high-grade epithelial carcinoma of the ovary.