This study reports the results of a comprehensive care program for pregnant addicts, one that provides medical, counseling, and child development services. Findings include the following. Women who enroll while pregnant generally stay through childbirth, and most deliveries are free of complication. Most newborns are of normal gestational age and birthweight, and these outcomes are directly related to length and amount of prenatal care. Neonatal withdrawal is directly related to prenatal maternal methadone dose. Child development, as measured by the Bayley Scales, is usually in the normal range, although mean scores for cognitive development decrease through age 2. Female babies generally have higher cognitive and motor scores than males, and their cognitive scores decline less sharply than those of the males. Developmental scores are directly related to neonatal maturity, especially birthweight. Prenatal maternal methadone dose tends to be negatively related to developmental scores for boys but not for girls.