Teratomas are predominantly tumors of infancy, usually detected during the first two years of life and occurring twice as frequently in male as in female children. Like other tumors of childhood, they often are benign but have serious potentialities of malignancy. The author describes several types of teratomas removed at the Children's Hospital, Louisville. He suggests microscopic diagnosis within 24 to 48 hours after a patient's admission to the hospital, with total excision the only logical procedure.