INTRODUCTION : Recently, intramedullary nailing is the treatment of choice in the management of fractures in the tibial diaphysis. But fractures of the proximal third of the tibial shaft including segmental fractures do not appear to respond as favorably to intramedullaryu nailing as do fractures in the distal 2/3 of the tibia. One of the msot frequent complications of intramedullary nailing of proximal third tibia is fracture malalignment leading to anterior angulation, anterior displacement or valgus angulation. There are several factors combine to make these fractures difficult to reduce when nailing. 1) The pull of the patellar tendon and muscles around the proximal tibia on the shory proximal fracture fragment. 2) The traditional medial entrance point of nailing in the proximal tibia. The author`s objective is to introduce a new technique to neutralize these factors so that intramedullary nailing can be consistently used to treat poximal third ribia fractures. MATERIALS AND METHODS : Five of proximal third tibial shaft including one segmental fracture were treated with a new technique for intramedullary nailing of these fractures. The clinical summary was s belows. 1) Inserted two 0.125inch Steinmann pins at the proximal tibial fragment, which authors called as 'blocking pin'. These pins were crossed with 10-15degree angle at midpoint of the proximal tibia anteroposteriorly and mediolaterally. 3) Made the entrance hole using awl which was introduced just anterior to the cross point of two blocking pins. 4) The AO unreamed tibial nail was inserted anterior to two blocking pins, After then, continued the nail insertion with closed technique. 5) Performed proximal(3 screws) and distal(2 or 3 screws) locking. 6) Removed two blocking pins finally. Outcomes were evaluated immediately postoperatively and at follow-up visit by measurement of alignment in both the anteroposterior and lateral planes. All patient were evaluated clinically also. RESULTS : The average anterior angulation and anterior displacement immediately postoperatively were 3.0degree (range 1degree to 5degree) and 2.8mm (range 1mm to 4mm) respectively. The average coronal plane alignement was 3.2degree valgus(range 2degree to4degree valgus). There was no complication from the use of this technique either intraoperatively or postoperatively. Fracture alignment at the time of last follow-up was unchanged from immediate postoperative measurements. All 5 cases healed clinically and radiologically. In 3 casesm bone graft was performed at postoperative 6 weeks due to delayed union. The average time to radiologic healing was 21weeks(17-26 weeks). CONCLUSIONS : Intramedullary nailing of proximal third tibial fractures including segmental fractures is technically demending and has a problem of the high rate of malalignments. However, through a new technique above mentioned which neutralize deforming factors, reliable alignments and healing were achieved successfully in proximal third tibial fractures. The authors introduce and recommend a new technique in intramedullary nailing to treat the authors introduce and recommend a new technique in intramedullary nailing to treat the fractures of the proximal third of the tibial shaft(esp. segmental fractures).