Athetosis in infancy and childhood is primarily the result of anoxia associated with the birth of the infant. A secondary factor is icterus and Rh incompatibility, especially in the deaf athetoid. The family background, and period of pregnancy appear to play no role in the etiology of athetosis. The order of pregnancy is highly significant, the risk of pathology being enhanced with the first delivery. The finding that anoxia plays the paramount role, is consistent with proven pathological studies which have revealed changes in the brain associated with anoxia. The incidence of athetosis may be lessened if the primary factors which lead to anoxia, Rh incompatibility and icterus, are avoided or controlled.