The clinicopathologic experience of 10 patients with immature ovarian teratoma is presented. The mean age of the patients was 22.1. Abdominopelvic mass was the presenting symptom in the majority of cases. Immature ovarian teratomas accounted for 4.0% of germ cell tumors and 2.1% of all ovarian neoplasms diagnosed in our institution. Of the patients, 6 had Stage I disease and 7 had grade I tumor. Unilateral tumor was encountered in the majority of patients. Adequate primary surgical-pathologic staging and multiagent chemotherapy seem to be the treatment of choice.