Ganglioneuroblastoma is the neurogenic tumor arising from the sympathetic ganglia which extends from the baseof skull to the pelvis including the suprarenal medulla. Pathologically it belongs to the intermediate group between malignant neuroblastoma and benign ganglioneuroma. It most frequently occurs in the infant and young children, predominantly at the posterior mediastinum. Here the authors report a case of ganglioneuroblastoma of posterior mediastinum in a 12 year old boy which was recently confirmed histopathologically at Severance Hospital, Yonsei University. Radiological aspects are reviewed as well as clinical and pathological aspects along with brief review of references.