Twenty-five patients with unstable fracture or fracture-dislocation of the thoracolumbar and lumbar spines were treated with Cotrel-Dubousset instrumentation. Internal fixation was done in two ways; long rodding in seventeen patients and short rodding in eight. Short segment posterolateral or posterior autogenous iliac bone graft was done in all cases. The amount of correction of the collapsed anterior vertebral body height and the local kyphotic angle at the immediate post-operation were similar between the two groups, but loss of correction at last follow-up was more severe in the short rodding group. Instrument failure was also more common in the short rodding group. In conclusion, it was found that short segment stabilization of spine fractures with Cotrel-Dubousset instrument can effectively reduce fracture but can not maintain reduction until fusion. Therefore, long rodding was reconfirmed to be the better method of stabilization of the thoracolumbar and lumbar spines fractures.