Treatment of patients with advanced ovarian carcinoma (stages IIIB and IV) using either cyclophosphamide alone (1 g/m2) or cyclophosphamide (500 mg/m2) plus adriamycin (40 mg/m2) by iv injection every 3 weeks each produced partial regression in approximately one third of the patients. Survival curves and time-to-progression curves for the two regimens were nearly identical in these patients with advanced disease. These same regimens produced different results when used monthly in patients who had minimal residual disease (stages II and IIIA). In patients with minimal residual disease the therapeutic index of the combination regimen was superior to that of cyclophosphamide alone. Prognosis was better overall among patients with minimal residual disease than among patients with advanced disease. Within the minimal-disease group grossly complete excision of tumor prior to chemotherapy was associated with still better prognosis. Among patients with advanced disease, prognosis was significantly better for older patients despite their generally less favorable performance scores. Much of this prognostic superiority appeared to be related to menopausal status and presumably to the depletion of endogenous estrogens in the older patients.