Abstract: This paper presents a computerized bone age assessment method using discrete cosine transform (DCT) and Fisher's linear discriminant analysis (FLD or LDA). Bone age assessment using a radiograph of the left hand is a common procedure in pediatric radiology. In the proposed method, DCT and LDA are applied to the epiphyseal regions segmented from a radiograph of the left hand. The extracted LDA coefficients are compared with features stored in the database, and then the bone age of the given radiograph is estimated. In experiments on 396 radiographs of the left hand collected at Hanyang University Medical Center, the proposed method shows an average error of 0.6 years and an accuracy of 89.71%.