Computed Tomography (CT) examinations of orbit have attained a preeminent position as a noninvasive safe technique for the evaluation of man orbital problems because intraorbital fat with inherent low density provides a natural contrast to all softtissue structures within the orbits, normal or abnormal. In our study, radiologic analysis was made on CT findings of 40 cases c pathologically proven orbital space-occupying lesion during the 3 years from 1986 to 1988. The results were as follows : 1. The incidence of orbital lesions bases on location was most common in extraconal area (15 cases), followed by intraocular (12 cases), extraorbital (8 cases), intraconal (4 cases), and muscle cone (1 cases). 2. The incidence of orbital tumors was most common in retinoblastoma (8 cases0, intraconal (4 cases), and muscle cone (1 cases). 2. The incidence of orbital tumors was most common in retinoblastoma 98 cases), followed by pseudotumor (6 cases), and hemangioma (3 cases). 3. Choroidal elanoma & hemangioma occured in elderly and retinoblastoma, teratoma, endodermal sinus tumor occured in young chiledren. 4. Retinoblastoma combined with calcification in 88% and extraocular extension in 2 cases. 5. In the differential diagnosis, indivisual characteristics are useful in teratoma, epidermoid cyst, hemangioma and retinoblastoma, And locatins of the lesions are useful in lacrimal gland tumor, epidermord cyst and hemangioma. Intravenous contrast media is very useful in detection of vascular tumors, pseudotumors and their extent. 6. Indivisual characteristic lesion & relations to the adjacent structures were well analyzed by thin slice section and reconstruction of data from axial scanning into coronal, and sagittal planes. 7. Exact tumor detection & localization were possible in all cases. Therefore, CT scanning is useful method in differentiating orbital lesions & its extent.