Acute abdomen with hemoperitoneum is a very rare entity in postmenopausal women due to gynecologic conditions. A 54-year-old, postmenopausal woman was brought to emergency department with severe abdominal pain. Physical examination revealed acute abdomen findings with 15 cm pelvic mass on the right adnexal region. Immediate exploratory laparotomy was performed. During laparotomy 1000 cc of bloodstained fluid, ruptured and actively bleeding large mass arising from right ovary was observed. Right salpingo-oopherectomy was performed in emergency conditions, and pathology report revealed an adult type of granulosa cell tumor. After this result, staging surgery was performed and patient was diagnosed as granulosa cell tumor stage 1 c. Cisplatin, etoposide, and bleomycin chemotherapy was given. Clinicians should be aware of granulosa cell tumors which may occur at any age and prone to rupture. Frozen section will be helpful in order to avoid incomplete surgeries especially in postmenopausal women presented with intra-abdominal bleeding.