Authors retrospectively analayzed CT findings of 10 findings of 10 cases which proved retinoblastoma by pathology from may in 1983 to August in 1986 at Yeungnam univ. hospital. RESULT: 1. The age at time of diagnosis was 1-5 year old. 2. In 9 cases, retinoblatoma was unilateral. 3. Of all 10 cawses, 8 cases revealed intraocular calcification. 4 At time of diagnosis of retinoblastoma, optic nerve involvement with or without intracranial extension were 2 cases. The diagnosis of retinoblastoma can be made clinically, but CT is valuable adjunct in differential diagnosis and mangement as well as diagnosis of retinoblastoma. In addition, orbital CT can be used to determine if there is retrobubal extension of retinoblastoma, involvement of CNS, and development of secondary orbital tumors.