Seven cases of immature teratoma of the ovary with a neural component were analysed in the past 10 years. These constituted 1. 75 per cent

of all ovary tumors collected in the same period. All the primary tumors in the present series contained at least some immature tissues(predominantly of neural origin) and were thus graded from 1 to 3 according to the criteria of Norris. A close relationship definitely exists between the histologic grade of the tumor and that of the survival in patients. 6 of the 7 cases had been followed up; 2 cases with grade III died in several months after operation and 4 cases with grade I or II have survived. Immature teratoma of the ovary is a unioue malignancy. The diagnosis and treatment of these tumors are discussed