The clinicopathologic and immunohistochemical findings of a case of coexistent primary ovarian rhabdomyosarcoma and clear cell carcinoma of the ovary are reported. The tumor was detected in a 41-year-old premenopausal woman who had a 1-year history of pelvic pain. On physical examination, a 14.0-cm left adnexal mass was found for which a hysterectomy with bilateral salpingo-oophorectomy and staging biopsies were performed. The tumor was composed of solid and cystic areas, and two distinct microscopic components were identified: clear cell carcinoma and rhabdomyosarcoma. Immunoperoxidase studies demonstrated that the neoplastic cells in the latter component were positive for desmin, muscle-specific actin, and myoglobin. A biopsy taken from the pelvic peritoneum revealed rhabdomyosarcoma (FIGO stage IIB). Despite two cycles of chemotherapy, the disease persisted in the pelvis 4 months after diagnosis.