The development of computed tomography [provided a noninvasive safe technique for imaging the orbit in any plane exquisitely demonstrating its normal anatomy as well as its pathologic process. The orbit is an ideal structure to be examined by CT because of large difference of absortion values between the intraorbgital fat, muscle, optic nerve and vessels. In this study, the authors reviewed CT findings of 66 pathologically proven orbital tumors and tumorous conditions among the total of 98 cases who had taken orbital CT scan because of exophthalmos, ocular pain, diplopia and other ophthalmologic symptoms suggesting orbital masses during the period of 3 years. RESULT : 1. Exact tumor detecton and localization was possible in 63 cases. Thus the detection rate was 95% with CT scan. 2. Among 36 males and 30 females, their age ranged from 10 months to 72 years. 3. Intraocular tumors were 10 cases. Retinoblastoma occurred wholly in the young children under 5 years and combined with alcification in 57%. Choroidal melanoma occurred wholly in adults. 4. Intraconal tumor were 9 cases. Vascular tumors were the most frequent and well enhancing mass. 5. The tumors arising inthe extraconal region were pseudotumor, lymphoma, dermoid cyst, metastasis, adenoid cystic carcinoma and teratoma. 6. The lesions arising from extraorbital region were PNS cancer, mucocele, lid cancer, fibrous dysplasia and neurofibromatosis. 7. Thin slice thickness of the transverse axial scan and reconstruction of image in various planes provide better 3 dimensional image and are useful for the evaluation of the characteristics of the mass and its relation to other structures. 8. Contrast enhanement is useful in differentiation of vascular tumors and other nonvascular tumors, and evaluation of the scleral thickening in pseudotumors. Evaluation of tumor extension is also possible with contrast enhancement, but in extraconal mass contrast enhacement was not helpful. 9. The CT is the method of choic in the detection and differential diagnosis of t