A case of ovarian immature teratoma with rhabdoniyosarcomatous recurrence in a 6-year-old girt is described. The primary tumor consisted of a dermoid cyst and a solid nodule composed of mature and immature mesenchymal tissue. The most immature mesenchymal cells showed no distinctive differentiation except for focal rhabdomyoblastic differentiation . The primary tumor was diagnosed as immature teratoma. grade 2, stage IIa. Despite left oophorectomy and excision of uterine serosal implants, chemotherapy. and radiation, four intrapelvic recurrences developed within 3 years. Although the primary tumor contained only a few, rhabdomyoblasts, the recur-rent rumors became increasingly rhabdomyosarcomatous. The patient died of systemic disease 3 years after presentation. This case and previous reports indicate that the prognosis of patients with ovarian immature teratoma with rhabdoniyosarcomatous recurrence is poor and similar to that of primary ovarian rhabdomyosarcoma.