To evaluate the 3-year behavioral and developmental outcome of children prenatally exposed to maternal substances of abuse.Ninety-three children exposed prenatally to cocaine and other drugs taken by the mother during pregnancy (Group 1), 24 polydrug/noncocaine exposed children (Group 2), and 25 nonexposed children (Group 3) were evaluated at 3 years of age as part of a longitudinal prospective study of the impact of intrauterine substance exposure on long-term outcome. The Stanford-Binet Intelligence Scale: Fourth Edition(SBIS) was administered by examiners blinded to the exposure background of the children, and a pediatrician performed a complete medical evaluation on all the children. The children's primary caregiver completed the Achenbach Child Behavior Checklist. Stepwise multiple regression procedures were used to determine the factors that best predicted 3-year growth, intelligence, and behavior.Groups 1 and 2 differed from Group 3 on head circumference. Group 1 scored lower than Group 3 on SBIS Verbal Reasoning. Group 2 scored Slower than Group 3 on SBIS Abstract/Visual Reasoning. Cocaine exposure predicted poor verbal reasoning. Marijuana exposure predicted poor abstract/visual reasoning. Examiner rating predicted intellectual outcome and caregiver ratings. Caregivers rated exposed children as more aggressive than nonexposed.Contrary to information in the popular media, not all substance-exposed children suffer the same poor prognosis. In fact, generalizations about the fate of drug-exposed children must await additional research into the outcome of the broader population of drug-exposed children, examining the roles of maternal and environmental factors across a variety of geographic locations and socioeconomic levels.