The aim of present study is to introduce Theissing technique for managing pure blow-out fractures of the orbital floor and to evaluate the surgical outcomes. A retrospective study was done in 12 patients(9 males and 3 females, aged 16 to 48 years;mean 28.6 years) with pure blow-out fractures of the orbital floor who inderwent operations via Theissing technique in Gyeongsang National University Hospital from June 1991 through May 1995. Three of 12 cases had simultaneous blow-out fractures on the medial wall of orbit. They were followed up for 3-16 months(mean 6.1 months) postoperatively. Preoperative ophthalmologic and computerized tomographic(CT) findings were compared with the postoperative third month's findings. Pure blow-out fractures of the orbital floor usually occurred in young males by physical contacts such as fist fights. There were no cases with visual disturbance preoperatively and their visions were preserved postoperatively. Diplopia and/or limitation of eyeball movement disappeared postoperatively in all cases with those manifestations. Of 11 cases with enophthalmos present or predicted, nine(81.8%) showed improvement postoperatively. Eleven(91.7%) of 12 cases had good or fair outcome of fracture reduction in postoperative CT. The prognosis of enophthalmos was not related to the interval between injury and operation, but related to the preoperative severity of fracture with displacement. In conclusion, Theissinf technique is an eggective metod for managing pure blow-out fractures of the orbital floor. Especially for the patients with medical problems that would not permit general anesthesia, it may be an alternative to the other techniques because it can be performed under local anesthesia.