Abstract: Background: Thoracolumbar area of the spine is the most common site for injuries and the surgical treatment of fixation for treatment of these fractures remain controversy. Objectives: to evaluate the failure rate of short and long segment fixation of post traumatic thoracolumbar fractures. Methods: 40 patients had been taken and divided into two groups I andII; each category consists of 20 patients whom undergo fracture at thoracolumbar region (D11, D12, L1, L2 or L3). Group I was operated by short segment posterior fixation (one level above and one level below fractured vertebrae) while group II was operated by long segment posterior fixation (two levels above, two levels below or two levels above, one level below or one level above and two levels below).All cases were followed up clinically for improvement of neurological deficits & late postoperative complications (broken screws, kyphosis and back pain).Also all cases had been followed up radiologically by plain radiogram +/- C.T. scan for assessment of the instrumental system, decompression & improvement of kyphotic deformities. Operation’s time and the amount of blood loss were considered. Follow up at least six months. Results: Complications are more in short segment fixation (30%) than long segment fixation (5%). Back pain is the most common complication followed by post-operative kyphosis then system failure (broken screw or dislodgment). Blood loss and time of surgical procedure in short segment fixation (SS) is less than long segment fixation (LS).Conclusion: The surgical treatment of unstable thoracolumbar fractures using a short fixation showed greater loss of kyphosis correction in the long-term follow-up of patients and high rate of instrumental failure, compared to long fixation. These radiographic findings make long fixation an effective option in the management of thoracolumbar fractures. Despite the higher rate of failures with short fixation, it has shorter surgical times and less blood loss.