OBJECTIVE: The purpose of this study was to evaluate the clinical characteristics, surgical procedures, adjuvant treatment and prognostic factors in women with adult granulosa cell tumor of the ovary METHOD: We identified 32 patients with adult granulosa cell tumor who were treated at Asan Medical Center from September 1991 to December 2003. All clinical data about these patients were obtained from the medical records. Data were statistically analyzed using the Kaplan-Meier method and the Log-rank test. RESULTS: The mean age was 45.1 years(range 23-85 years) and mean follow up was 44.4 months(range 1-146 month). According to the FIGO criteria, 26 of 32 patients(81.3%) were in stage I, one(3.1%) was in stage II, 5(15.6%) were in stage III. All patients had surgical operation and 11 received chemotherapy and one received radiation therapy. Two patients were dead and recurrence occurred in two cases. Overall 5 year survival rate was 90.5 %, and mean survival time was 134 months(95% Confidence Interval, 116-150 months). According to the univariant analysis, overall survival of the early stage(stage I, II) was better than that of the advanced stage(stage III) (p=0.0009). Other clinical parameter, such as age, menopause, tumor size, tumor rupture, CA-125 level were not statistically significant. CONCLUSION: Granulosa cell tumor have better prognosis than other ovarian cancer. But long-term follow up is recommended due to its late recurrence. And the stage was the only statistically significant prognostic factor in this study.