PURPOSE: Anatomical basis around orbit can be helpful in periorbital surgery, and there are many articles about measurement between periorbital reference points. In 1967, Jones and Evans measured the orbital wall thickness of Asian cadavers and this article has been cited more than 50 times. But there is no research in orbital thickness in Vivo. Author's idea was based on difference between live human and human cadaver. MATERIAL & METHOD: We conducted this study from 63 consecutive blow out fracture patients between January, 2000 to june, 2005 by collecting the bone fragments and measured the thickness of that fragment using vernia calipers. Anatomically, orbital floor is separated two area by inferior orbital fissure and we measured each area. Three areas were zone I(medial wall), zone II(medial to inferior orbital fissure) and zone III(lateral to inferior orbital fissure). Result: When the overall results were considered, the thickness of Zone I(medial wall of orbit) was average 0.131 +/-0.006mm in male and 0.129+/-0.007mm in female and Zone II(medial side of orbital floor) was 0.251+/-0.005mm in male and 0.245+/-0.006mm in female, Zone III(lateral side of orbital floor) was 0.237+/-0.006mm in male and 0.226+/-0.006mm in female. There were no statistical difference between orbital wall thickness of male and female. Also, orbital wall thickness of adults measured 0.130+/-0.005mm, 0.250+/-0.005mm, 0.232+/-0.006mm in Zone I, Zone II, Zone III and 0.128+/-0.006mm, 0.233+/-0.005mm, 0.215+/-0.007mm in Zone I, Zone II, Zone III from childs, and there were no statistical difference between adult and child. CONCLUSION: This article is the first study about Korean orbital wall thickness, and can be helpful to periocular surgery.