The inhibiting and destructive effects of roentgen rays on epiphyseal cartilage have been demonstrated in the animal by a number of investigators. During the first decade of the twentieth century Perthes, Recamier andTribondeau subjected animals to irradiation, demonstrating that exposure to X-ray caused more or less retardationin the growth of bones and other structures. In later years, animal studies have been conducted by Barr(1943),Bisgurd and Hunt (1936), Regan and Wilkins (1936) Their observations demonstrate without question hat bone growthin the young can be retarded or stopped by a sufficient disage of X-ray. The literature dose not divulage a largenumber of cases in which longitudinal growth was followed after therapeutic irradiation about the epiphyses,although Desjardins (1930), Judy (1941), Spangler (1941) and Frantz (1950) reported. We have observed a case ofstunting of bone growth of 3 months age of infant followed after therapeutic X-irradiation of haemoangioma ofright lower leg. The degree of retardation of bone growth were 8.0cm for the tibia and 2.6cm for the fibula infour years after irradiation.