Primary ovarian fibrosarcoma is an exceedingly rare malignant ovarian stromal tumor which has a poor prognosis. We report here a 46-year-old woman who suffered from irregular vaginal bleeding for 2 months. She received hysterectomy and salpingo-oophorectomy due to a provisional diagnosis of uterine and ovarian tumors. At surgery, an 8-cm ovarian solid multilobular tumor was found. Frozen section examination revealed an ovarian fibrosarcoma. She then underwent staging procedures including intraperitoneal washing, cytology, and pelvic and para-aortic lymph node sampling. Final pathologic examination revealed that the tumor exhibited densely packed spindle cells in storiform configuration with obvious increased mitotic activity. In addition, the flow cytometric study showed marked elevated percentage of tumor cells in the S phase (13.1%). After surgery, the patient received six courses of combination chemotherapy with epirubicin, ifosfamide, and dacarbazine (DTIC). The patient stood the treatment well and is free from disease 6 years later.