Objectives : The purpose of this study was to evaluate the correlation of 3 methods of bone age measurements. Methods : 102 children(49 boys, 53 girls) were involved in this study. We measured the height, weight and bone age based when they visited for the first time. We measured bone age using BoneAge of Sunlight Co.,Ltd. Two of the bone age measurement methods, Greulich-Pyle and Tanner-Whitehouse, were used to analyze the left dorsopalmar hand-wrist radiographs of 102 children who visited in Department of Pediatrics, O O University Oriental Hospital. This study was designed to investigate the correlation of the bone age between two methods. Results : The bone ages were related with age, height, weight and BMI according to this study(P<0.01). Each bone age assessment method had statistically significant correlation to each other(P<0.01). Conclusions : The ultrasound transonic velocity of inferior radiocarpal joint will become a sufficient diagnostic tool of bone age assessment if measurement error can be minimized by proper effort.