On the pulse from the trauma transiting to posterior side of the orbit, orbital fractures are occurred throughthe weak point of the orbital wall. Invagination of soft tissue or entrapment of muscles may be associated withorbital fracture. In condition of inaccurate diagnosis, appropriate surgical repairment is impossible andcomplications such as diplopia or enophthalmia are developed. CT scan is diagnostic procedure which demonstratesaccurately the site and stage of orbital fracture, and its associated findings. The authors has been studied in 21orbital CT scans to evaluate the relative value of plain X rays and CT scans in the diagnosis of orbital fracturesduring the period from January 1982 to September 1985. The conclusions were as follows: 1. Diagnostic rate was100% by CT, 40% by initial and 80% by retrospective interpretation of conventional X-ray films. 2. Low X-raydiagnostic rate of medical wall fractures(26.7%) was due to thinness of the bone. 3. Medial wall fractures wereassociated with floor fractures in 46%. 4. Orbital soft tissue injuries and abnormalities of PNS were preciselyevaluated by CT scan.