Ovarian heterologous sarcoma is a rare malignancy. Only three cases of ovarian chondrosarcoma have been reported in the literature, and almost all of these were components of ovarian teratomas. Herein, we report the clinicopathological characteristics of an ovarian chondrosarcoma in a 68-year-old woman who had previously undergone total hysterectomy. She had no subjective symptoms, and the tumor was unexpectedly found by further examination of osteoarthritis of the hip joint. Preoperative magnetic resonance imaging revealed curious findings of a lobulated high-intensity component with a leaf-vein-like low-intensity component. Computed tomography revealed irregularly distributed ossification extending to the entire tumor. Preoperative levels of CA125, CA19-9, carcinoembryonic antigen, α-fetoprotein, and lactic dehydrogenase were all within normal limits. Macroscopic findings of the surgically resected tumor and pathologic findings revealed no teratoma component in the tumor. Finally, we diagnosed the tumor as a primary chondrosarcoma of the ovary.