Malformations of the hand in newborn infants are comparatively uncommon, and the forms which these malformations assume are extremely varied, some being so bizzare as to almost defy description. The etiology of congenital anomalies of the hand has not been conclusively established, but at the present time the most acceptable theories are those of maldevelopment due to teratogens or of mutations which are subsequently inhereted. This paper is based upon our own series of 99 anomalies in 93 patients who were hospitalized and treated at Severance Hospital during the period between 1965 and 1979 and the following results were obtained. 1. There were 56 males and 37 females in 93 patients and the ratio between male and female was 1.5: 1. 2. Right hands were involved in 49 patients, left hands were in 33 patients, and both hands were in 11 patients. 3. The most common type of anomalies were polydactylism (60.6%), next were syndactylism (24.3%), and the following anomalies were found; congenital finger deficiency, congenital constriction band, camptodactyly, cleft hand, congenital clasped thumb, and symphalangism. 4. 33 associated congenital anomalies were found in 27 patients, in which, anomalies of the foot were most common. 5. Prenatal history such as drug ingestion, eclampsia or difficult labor, and prematurity were found, but no genetic or familial history could be obtainable. 6. Treatment was stressed upon the function of hand rather than cosmetic appearance.