PURPOSE: This was a retrospective study to evaluate the results of intramedullary nailing in proximal shaft fracture of tibia. We analyzed those results according to AO classification and Poller screw. MATERIALS AND METHODS: Thirty-three proximal tibial shaft fractures (32 patients) were followed for more than one year. In AO classification, there were 6 cases of type A, 14 cases of type B, and 13 cases of type C. We used Poller screws in 14 operations. We evaluated translation, angulation and nonunion after surgeries. RESULTS: Twenty-eight cases (85%) were united primarily, but nonunions occurred in 5 cases. Malalignment (angulation>5degree or translation>5 mm) was found in 14 cases (42%). In Poller screw used and non-used groups, the malalignment was respectively showed in 2 cases (14%) and 12 cases (63%). According to AO classification, nonunion was found in only type B with 5 cases (36%). CONCLUSION: Intramedullary nailing of proximal shaft fracture of tibia showed relatively lower rate of primary union. Especially, when initial fractures have a butterfly fragment, it showed the higher rate of nonunion. Moreover, the malalignment rate was relatively higher, yet it is possible to reduce the rate of malalignment by using Poller screw.