Tibial bony defect causes severe angular deformity and instability, requiring accurate correction of bony defect. The purpose of this study is to analyze the results of TKA with wedge or block in augmenting tibial bony defect, and to find out the adequate method of treatment. Among 301 cases of TKA operated at Asan Medical Center from Sep. 1993 to Sep. 1997, authors analyzed 58 cases of tibial bone defect corrected by metal wedge or block. Mean follow up period was 25.1 months. All cases were divided into two groups; group A (37 cases) with wedge and group B (21 cases) with block. The results were as follows: 1. There were no definite statistical difference between group A and group B in HSS knee score, ROM, and correction of deformity. 2. Loosening of the implant was not noted, but 12 cases of mild bony resorption was found just beneath the wedge or block. It was more prominent in group A (9 cases) than in group B (3 cases). 3. Three cases of deep infection developed only in group A, which were followed by revision TKA. Although further follow up study should be carried out, we concluded that metal augmentation is good substitute to augment tibial bony defect in primary TKA.