The treatment of proximal tibial shaft fractures is an area of great controversy. The purpose of this study was to make the comparison between the results of the plate fixation and those of the interlocking nailing, and to identify the effects of the location of the nail bend on the reduction of the proximal tibial shaft fractures. From June 1991 to May 1995, we performed the plate fixation in 12 cases and interlocking nailing in 16 cases for the proximal tibial shaft fracture. We subdivided the interlocking nailing group into two groups: Group A had the fractures within the posterior bending length of the nail in 8 cases, Group B had the fractures over the posterior bending length of the nail in 8 cases. The results were as follows; The most common type of fractures was the Winquist-Han son type III, 9 cases(75%), in the plate fixation group, and the segmental fracture, 10 cases(62.5%), in the interlocking nailing group. In the plate fixation group, autogenous bone graft were used in 7 cases (58.3%), primary in 5 cases and secondary in 2 cases. The interlocking nailing group had a tendency to cause the surgical problems during the nailing such as angular deformity in 3 cases, displacement of the fracture in 2 cases, extension of the fracture in one case, need an open reduction in one case and unstable fixation in one case. The surgical problems were associatied with the incorrect entry point and the fractures within the posterior bending length of the nail (Group A). Clinically excellent and good results, according to Klemm and Borner criteria, were obtained in 12 cases(100%) of the plate fixation group and 13 cases(81.3%) of the interlocking nailing group. the fair results were associtated with the angular deformity in the Group A. In conclusion, the preoperative planing must carefully consider such as the type of fracture, technical familarity, and understanding of the implants and instrumentations ofr the successful treatment of the proximal tibial shaft fractures. The plate fixation is preferable method for the fractures within the posterior bending length of the nail(Group A).