We evaluated early social risk assessment as a predictor of cognitive development in high-risk infants. A social worker assessed social risk in 122 infants before discharge from a neonatal intensive care unit. Infants were evaluated at ages 12 and 36 months adjusted for prematurity. We found no difference in 12-month cognitive development among medical, neurologic, or social risk groups. However, from 12 to 36 months there was a significant decline in mean developmental quotient in the groups with social risk alone, neurologic and social risk, and medical and social risk, but not in the groups with medical or neurologic risks without social risk. Social risk assessment correctly predicted 36-month cognitive outcome in 71% of infants who had normal findings at 12 months. We conclude that neonatal social risk assessment can help identify infants at highest risk for cognitive retardation and is particularly important for infants who have medical or neurologic problems.