The effects of intrauterine cocaine exposure on 158 low-birthweight infants (500 g to 2500 g) were compared with 536 low-birthweight infants not known to be exposed to cocaine who were admitted to our neonatal intensive care unit. Univariate analyses indicated that drug-exposed infants had lower birthweights when compared with control infants. Frequency of necrotizing enterocolitis differed between the drug-exposed infants and controls (11% versus 6%). Frequency of severe respiratory distress syndrome, severe intraventricular hemorrhage, and bronchopulmonary dysplasia did not differ between groups of similar birthweight. We conclude that the most evident risks of prenatal cocaine exposure are low birthweight and increased incidence of necrotizing enterocolitis.