In an attempt to understand better the complex etiologies of child abuse and neglect, this investigation is following 275 high-risk mothers and infants through the child's first year of life. In the present study, the characteristics of a group of primiparous women, infant temperament, mother-infant interaction, and environmental stress factors are examined to identify variables that differentiate mothers who mistreat their children from those who do not. A subsample of 25 mothers providing good quality care and 26 mothers who have abused or in some way mistreated their children has been identified. The inadequate mothers had more pregnancy and birth complications, but there was little difference in the babies' temperament except that the babies in the good mother group were better able to orient and were less irritable. The good mothers were older, better educated, had more support from alleged father and family, and, in general, were much better prepared for the baby. There was basically no difference in personality characteristics or amount of life stress experienced by the two groups of mothers. The variables that best differentiated the two groups were: mother's understanding of the psychological complexity of the infant and her relationship with the infant; and a factor based on observations of mother's care-taking skills, her positive affect, and infant's social responsiveness.