Purpose of investigation: Primary sarcomas account for of 2-3% of all female genital tract cancers and ovaries are unusual sites for sarcomas. The authors aimed to report a case of primary ovarian sarcoma. Materials and Methods:A 46-year-old woman presented with abdominal pain and distention. Abdominal MRI revealed a 20-cm-sized complex mass in the right adnexa and ascites. Preoperative CA-125 was 289 U/ml. She underwent optimal debulking surgery and diagnosed with undifferentiated pleomorphic sarcoma with focally rhabdomyosarcomatous differentiation. Results: The patient presented with severe abdominal pain and distention 32 days after the operation and recurrent disease was diagnosed. First cure of adjuvant chemotherapy was administered, but she died 15 days later. Conclusion: Coexistence of undifferentiated pleomorphic sarcoma and rhabdomyosarcoma shows highly aggressive behavior and its prognosis is extremely poor. To the best of the authors' knowledge, this is the second case report of the coexistence of these type tumors in the literature.