On the pulse from the trauma trannsiting to posterior side of the orbit, orbital fractures are occurred through the weak point of the orbital wall. Invagination of soft tissue or entrapment of muscles may be associated with orbital fracture. In condition of inaccurate diagnosis, appropriate surgical repairment is impossible and complications such as diplopia or enophthalmia are developed. CT scan is diagnostic procedure which demonstrates accurately the site and state of orbital fracture, and its associated findings. The authors has been studied in 21 orbital CT scans to evalute the relative value of plain X rays and CT scans in the diagnosis of orbital fractures during the period from January 1982 to Septemper 1985. The conclusions were as follows : 1. diagnostic rate was 100% by CT, 40% by initial and 80% by retrospective interpretation of convention al X-ray films. 2. Low X-ray diagnostic rate of medical wall fractures (26.7%) was due to thinness of the bone. 3. Medial wal fracutures were associated with floor fractures in 46%. 4. Orbital soft tissue injuries and abnormalities of PNS were precisely evaluated by CT scan.