The authors examined the role of familial risk and child characteristics in the association between the type of child care in infancy (maternal care [MC]) versus nonmaternal care [NMC]) and emotional/behavioral difficulties at 4 years old. Canadian families (N=1,358) with children between 1 and 12 months old were followed over 4 years. Family risks were found to moderate the association between type of child care and physical aggression. MC in infancy was associated with lower levels of physical aggression among children from a low-risk family background but not among those from a high-risk family background. The effect size was small (d=-0.16; confidence interval [CI]=-0.3, -0.01). Family risk and the sex of the child moderated the association between child care and emotional problems. MC in infancy was associated with a lower level of emotional difficulties among girls from low-risk families but not among boys or among children from high-risk families. The effect size was moderate (d=-0.44; CI=-0.65, -0.23). The study indicates that the effect of child care type in infancy varies by family and child characteristics.