Cervical spine injury, because of its increasing frequency and catastrophic neurological complication, has attracted many attention of every orthopedic surgeons. Moreover, the indications of surgical treatment and the indications of anterior or posterior fusion have been argued till now. Forty-one patients with cervical spine injury had been treated operatively at Department of Orthopedic Surgery, Seoul National University Hospital from January, 1980 to April, 1987. The surgically treated patients were followed up from 1 year to 7 years with average duration of 2.5years. We performed this study to define the advantages of the surgical treatment, the indications of the anterior and posterior fusion, the postoperative neurological changes, the importance of early reduction, and the result of surgical treatment in late instability cases and obtained the following results. 1. Flexion-rotation injury, in twenty three patients(56.0%), was the most frequent mechanism of injury. 2. Anterior decompression and fusion was performed in 8 patients(19.5%) when there were neural compression by fractured bone fragment or ruptured intervertebral disc material and rupture of anterior longitudinal ligament with hyperextension injury, without poterior ligament complex injury, and posterior fusion and wiring in 33 patients(80.5%) when there were upper cervical spine(C1, C2) injuries and posterior ligament complex injury. 3. Neurological involvements were observed in 35 patients(85.4%) on arrival, and partial and complete neurological recoveries were obtained in 20 patients(57.1%) out of 35 patients postoperatively. 4. Neurological recovery was obtained in 80% when the closed reduction was performed within 12 hours after the injury and only 40% after 12 hours. 5. Neck pain and/or neurology was improved in all 9 patients with late instability postoperatively. 6. Postoperative complication rate was totally 43.9%, but direct surgical complications were 2 cases(4.9%) out of 18 cases.