After discussing some of the issues in defining child abuse, this paper notes inadequacies in the official reporting of such abuse and consequent inaccuracies in incidence data. Discussions of causal theories and research on the causes and correlates of abuse are followed by a summary of current knowledge about factors related to physical child abuse. These include psychological factors (personality, intelligence, intergenerational transmission of abuse, childrearing approaches), social factors (stress, social isolation, social acceptance of violence), child factors, and parent-child interaction factors. Overall, the discussion indicates that child abuse is multiply determined, with different variables being important in individual cases. The paper concludes with discussions of treatment, prediction, and primary prevention. This summary of current knowledge about child physical abuse is intended as a foundation for future research, prevention, and social action. 231 references.