The goal of this study was to examine children's cognitive and language development and social engagement of mother as mediators of the relationship between maternal emotional availability at 15 months and children's empathy at the ages of two and four. Participants were 661 low-income, ethnically diverse mother-child dyads participating in a trial of home visitation in the Denver area. Using home- and lab-based free-play episodes, mothers' emotional availability (15 months) and children's social engagement of mother (21 and 24 months) were assessed. Standardized measures were used to assess children's language development (21 months) and cognitive development (24 months). Empathy was assessed using a simulated injury paradigm at ages two (both 21 and 24 months) and four. The predictive models supported the hypothesis that the child's cognitive and social resources mediate the relationship between maternal emotional availability and children's empathy with respect to empathy at the age of two toward both mothers and an unfamiliar examiner. These results indicate that parental sensitive behavior is not the only important condition for predicting children's empathy, and that children's own internalized resources are a likely mechanism of transmission from parents caring for their children to children learning to care for others.