TO determine the normal neonatal adrenal gland size, ultrasonographic examinations were performed in 145 newborn infants. They were divided into 3 groups according to the days of age. The group I is 1~3 days, group II is 6~9 days and group III is 21~50 days of age. 1) The adrenal gland size was as follows. In group I, the length was 29.05mm and the width was 4.02mm. In group II, the length was 24.04mm and the width was 2.79mm. In group III, the length was 19.54mm and the width was 2.21mm. 2) With increasing age, the size of adrenal gland became smaller. 3) The size of adrenal gland correlated well with the birth weight and height. We conclude that the ultrasonographic examination is useful in infant adrenal gland disease.