Objectives. The goal of this work was to evaluate clinical and pathological findings, surgical procedures, and postoperative treatment in women with stage I granulosa cell tumor. Methods. Data for 49 women with granulosa cell tumor were collected retrospectively. All pathological sections and findings were reviewed from diagnosis until recently. Follow-up data were collected from the general practitioner, hospital records, or death certificate. Fisher's exact test, Student's t test, Mann-Whitney test, and Kaplan-Meier survival analysis were applied, as appropriate. Results. Thirty-seven women of median age 58 years (range, 33-82) were diagnosed in stage I. Follow-up time was 8 years (range, 8 months to 26 years). The estimated survival for stage I was 93% at 5 years, 84% at 10 years, and 62% at 20 years; the actual survival rates were 94, 82, and 62% after 5, 10, and 20 years, respectively. Primary treatment consisting of total abdominal hysterectomy and bilateral salpingo-oophorectomy was associated with improved survival (P < 0.05) and tended to be associated with longer relapse-free interval (P < 0.06). The 10-year survival rate was 40% in postmenopausal women operated conservatively and more than 90% for the extensively treated women (P < 0.05). Evidence of increased estrogen secretion was found more often in postmenopausal woman as compared with premenopausal women (P < 0.01) but did not affect survival. No pathological parameter correlated with prognosis. Conclusion. Granulosa cell tumor is a tumor of unquestionable malignant potential and has a tendency for late relapses. Longtime follow-up is recommended, (C) 2001 Academic Press.