28 patients with ovarian immature teratoma were studied pathologically. Neoplasms with other germ cell elements were excluded. The ages ranged from 11 to 38. 71% were women under 25 years. Each primary tumor and metastatic lesion was graded histologically according to the criteria of Norris. Of these 28 cases, 11 were grade I; 11 grade II; and 6 grade III. The study showed that the stage of primary tumor is closely related to the prognosis. The likelihood of recurrence and metastasis could be determined by the grade of the primary tumor. The recurrence rate of grade I, II, and III were 0%, 44% and 100%, respectively. It also showed that the addition of hysterectomy and contralateral adnexectomy for grades II and III lesions did not improve the survival. One patient had been operated for 3 times to remove recurrences in the abdominal cavity and liver in a period of 25 months. The first and second recurrent tumors were grade III, but the third one was grade II showing that the immature teratoma tends to mature, but this conversion needs time. The authors support the opinion that repeated operations to remove the recurrences may improve the survival.