Orthofix, a unilateral external fixator is simple and easy to use and it's design is also convenient to reduce and maintain the fracture site. In addition, wide range of application is an another advantage because compression and distraction is possible in the central body. Authors reviewed 56 operations in 50 patients for whom Orthofix was applied for 4 years from march 1988 to february 1992 in Chonnam University Hospital. There were 46 males and 4 females. Twenty five patients(50%) were between 20 to 40 years of age. The indication was open fracture of the long bone in 27 cases, infected nonunion in 17 cases, bony defect in 4 cases, arthrodiastasis in 3 cases, arthrodesis in 2 cases and others in 3 cases. 1. There were 23 cases treated with Orthofix only until completion of treatment, 17 cases necessary to another methods of treatment, 14 cases maintaining Orthofix until now and 2 cases miscellaneous. 2. The duration of maintenance of Orthofix until completion of treatment in 20 cases of open fracture of long bone or infected nonunion was 9.5 months in average. 3. The bone union time averaged 9.5 months in above 20 cases and there was a little difference of bone union time between open fractures and infected nonunions. 4. Result of long term follow-up in 20 cases open fracture of long bone or infected are as follows; 12 cases(60%) have angulation less than 10° or length inequality less than 10mm, 14 cases(70%) have showed no limitation in range of motion or mild limitation of joint above and below the fracture site. 5. Complications, directly related to Orthofix, developed in 17 cases. There were 15 cases of pin tract infection and 2 cases of fixation loosening. Orthofix was considered as one of the excellent external fixation system, for it is simple and easy to use and could provide rigid fixation for difficult conditions in Orthopedic field such as open fracture, infected nonunion, bony defect and arthrodiatasis.