Data of an epidemiologic study of granulosa cell tumors in Israel are presented. During the 15-year period of the survey, 172 cases of granulosa cell tumors of the ovary were diagnosed. This represents a yearly incidence of 0.9/100,000 females. The incidence of occurrence was two times higher in women of European/American origin than in those of Asian/African origin. Most patients were 40 to 69 years old. The presenting symptoms were mainly those of abdominal distension and pain and changes in the menstrual pattern. Associated malignancy was relatively common. Carcinoma of the breast was present in 6.4% of patients and endometrial malignancy in 11%. Forty-five percent of patients were diagnosed at Stage I of the disease while 27% were detected at the advanced Stages, III and IV. Factors affecting the prognosis involved the clinical stage of the disease at diagnosis, the type of presenting symptoms, and to a limited extent, the age of the patient.