In a retrospective study of the period 1982-1985, the records of 29 narcotic-addicted mothers and their 42 babies were reviewed. All mothers were from socially deprived backgrounds, had a poor record of ante-natal attendance and had frequent admissions to hospital. Thirteen mothers had a past history of hepatitis B and four were HBsAg positive. The babies had significantly lower mean gestational age and mean birth weight than the control group. Features of withdrawal were recorded in 84% of babies where a history was available. A high incidence of twins (10.5%) was also observed. Testing for HIV antibody in more recent cases has revealed positive results in seven mothers and three babies; one infant has since died from acquired immune deficiency syndrome.