In a collaborative study of the relationship between maternal childrearing practices and children's aggression, 42 preschool-aged children were observed in free play and in doll play. Their mothers were interviewed, and the recorded information was analyzed in such a way as to provide a measure of the severity with which aggression at home was pihnished. The data therefore permit a comparison of the relative frequency and the kind of aggression occurring in children both in real life in the preschool and in the fantasy of doll play, under different degrees of punishment at home.