PURPOSE: Blowout fracture can lead to functional impairments and esthetic deformities such as impairment of ocular movement, diplopia, visual loss and enophthalmos. The object of this study is to present a classification and its analysis according to the computed tomographic scan in blowout fractures. We classified blow out fractures into three types according to the anatomical location of fracture, the size of the bone defect and the degree of periosteal injury by using the computed tomography scan. Each progress and complications were analyzed more than mean 1 year. METHODS: Among the 155 cases during 4 years, there were 11 cases of medial orbital wall fracture, 97 cases of inferior orbital wall fracture, 47 cases of combined type. The mean age of patients was 31.2 years, ranged from 8 to 84 years. RESULTS: According to our classification, surgical treatments through the nasoendoscopic approach, the subciliary approach, the transconjunctival approach or their combinations were performed in 116 patients, and conservative treatments were done in 46 patients. Presurgical clinical findings of diplopia, impairment of ocular movement, enophthalmos of more than 2 mm were present in 62 patients. After surgical treatment, clinical findings were remained in 7 patients. CONCLUSION: We think that our classification according to computed tomographic scan is helpful for the indication and it may decrease the complications such as impairment of ocular movement, diplopia, visual loss and enophthalmos.