PURPOSE: To evaluate the safety and usefulness of the short-segment posterior instrumentation and fusion in the treatment of thoracolumbar spine fractures. MATERIALS AND METHODS: Forty-two patients were treated by short-segment pedicle screw instrumentation and fusion between Oct. 1998. and Jan. 2004 by single surgeon. All patients were treated posteriorly and all the pedicle screws are monoaxial. Intraoperative rod bending and fixation technique was used to reduce the collapsed vertebral body and correct the kyphotic angle. The follow up duration is mean 2.1 year (1~6 year). The mean age is 40.2 year (18~60 year) old. The fractures were classified by Denis' classification and Load-Sharing Classification. Preoperative and postoperative changes of kyphotic angle and vertebral body height were measured. Denis' Pain Score and Work scales, Frankel neurologic grade were obtained during follow-up evaluation for patients. RESULTS: All the cases got solid bony union. Mean Load-Sharing Score was 7.3. Clinical results were good. The mean kyphotic angle was preoperatively 14.5 degree, immediate postoperatively 7.5 degree, and last follow up 9.2 degree. The mean anterior vertebral heights s were 60.8% preoperatively, 83.4% immediate postoperatively, and 79.5% last follow up. There was only one case of screw breakage but no revision operation due to loss of reduction. All the cases showed satisfactory clinical results. CONCLUSION: This study suggest that short-segment instrumentation and fusion using pedicle screw system for thoracolumbar spine fractures could lead to good results, if comminution of vertebral body is considered in the selection of approach.