The proximal tibial osteotomy is a procedure usually employed for osteoarthritis of the knee with a predominant single compartment involvement accompanied by pain and angular deformity. It has as its objective the shift of the gravitational line of weight from an involved to a relatively uninvolved side of knee. We studied the results of proximal tibial osteotomy in 30 patients (33knees). The mean age was 55.7 years, degenerative osteoarthritis was 31 cases (93.9%) and posttraumatic osteoarthritis was 2 cases (6.1%). The results were as follows; The average distance of osteotomy between the proximal plane and distal plane was 10.3mm. The average preoperative tibiofemoral angle was varus 3.8degrees and average postoperative tibiofemoral angle was valgus 7.6 degrees. The amount of upward displacement of fibular head after proximal tibial osteotomy was from 3mm to 16mm (mean 7.5mm). The preoperative knee rating scale was 52.9 and the postoperative knee rating scale was 78. The complications of proximal tibial osteotomy were 3 cases of transient peroneal nerve palsy and 2cases of Coventry staple loosening, but the nerve palsy was completely recovered and there were no need of staple removal.