We show here that subtle forms of maltreatment during infancy (below 1 year of age) have potential consequences for the functioning of the child's adrenocortical response system. Infants who received frequent corporal punishment (e.g., spanking) showed high hormonal reactivity to stress (a repeated separation from mother, combined with the presence of a stranger). In addition, infants who experienced frequent emotional withdrawal by their mothers (either as a result of maternal depression, or mother's strategic use of withdrawal as a control tactic) showed elevated baseline levels of cortisol. It was suggested that there are hormonal "costs" when mothers show response patterns (intentionally or unintentionally) that limit their utility as a means of buffering the child against stress. The hormonal responses shown by infants may alter the functioning of the hypothalamic-pituitary-adrenal (HPA) axis in ways that, if continued, may foster risk for immune disorders, sensitization to later stress, cognitive deficits, and social-emotional problems.