Combination chemotherapy consisting of hexamethylmelamine and cisplatin, alone or with doxorubicin hydrochloride, was given to 27 patients with advanced ovarian cancer who had disease progression with therapy including alkylating agents. Eighteen (67%) had greater than 50% regression of measurable disease or disease that could be evaluated but not measured, for a projected median duration of seven months. The projected median survival for all patients is nine months from the time of entry into the study and 33 months from the time of diagnosis of ovarian cancer. The treatment could be readily administered on an outpatient basis with a regimen of hydration and diuresis that nearly completely prevented platinum-induced renal tubular damage. Myelosuppression was severe in 11 patients (40%), but there was no treatment-related deaths. Agents of such high activity should be considered as components of initial therapy for stage III and IV cancers.