Observations concerning methadone treatment in 21 pregnancies of drug addicted women in Stockholm between 1982 and 1997 are presented. Fourteen per cent of new-born infants were small for gestational age, with head circumference less than--2 SD. None had congenital malformations, but neonatal abstinence occurred frequently. Mortality due to sudden infant death syndrome was also high. Five infants with severe neonatal abstinence were successfully treated with tinctura opii. It is essential that antenatal care for drug addicted pregnant women and subsequent care for their infants are concentrated at units in which a midwife, an obstetrician and a pediatrician with specific competence in drug abuse during pregnancy cooperate.