Tibial nonunion is often associated with the soft tissue atrophy and the local circulatory disturbance, so it is important to minimize the soft tissue injury and maintain the stability at fracture site for bone union. We reviewed 29 cases of subcortical onlay bone grafts and plate fixations for the nonunion and delayed union of tibial shafts, from Jan. 1988 through Jan. 1994. The results were as follows. 1. Twenty-nine patients who had nonunion of the tibia underwent subcortical cancellous onlay bone graft and plating, and 28 fractures(96.6%) went on to union. 2. Subcortical elevation or shingling of cortical bone fragments of the tibial cortex, is advocated to provide sound biological condition in atrophic soft tissue envelope. 3. Narrow DCP encouraged early motion and reliably promoted obtaining anatomical alignment. So, in treatment of protracted tibial nonunion, especially in an area with deficient soft tissue or unyielding scar tissue, subcortical onlay bone graft and plate fixation is very useful method, result in good union and no skin problem.