A retrospective case controlled study was carried out on 51 Chinese gravidas who had abused narcotics and who were delivered in a teaching hospital in Hong Kong. Heroin was the most commonly abused drug. The number of patients who changed from heroin to methadone was small. The major antenatal complications were late antenatal booking (average 28 weeks), prematurity (41%), small for gestational age baby (27.5%), antepartum haemorrhage (13.7%) and high prevalence of venereal disease (23.5%). The babies born to drug addicted mothers were on average 629 g lighter at birth, 5 cm smaller in head circumference and 7 cm shorter in body length. Neonatal withdrawal symptoms occurred in 83% of all drug exposed neonates. The perinatal mortality rate was 19.6 per 1,000 total birth which was 2.5 times that of the control group. There was one maternal death in our series. Drug addiction in pregnancy poses a major risk to both mother and child.