Children of HIV-infected women are likely to be profoundly affected by their mothers' infection, regardless of their own infection status and their number will increase with the spread of infection among women in Europe. This article describes the family circumstances and social care of 1,123 children born to HIV-infected women enrolled in the European Collaborative Study and followed prospectively from birth. Most mothers were white, married or cohabiting, asymptomatic and had a history of drug use, with 45% currently using injecting drugs at the time of enrollment. Seventy percent of children were cared for by their mothers and/or fathers consistently in their first four years of life, but by age eight an estimated 60% will have lived away from their parents (i.e. with foster or adoptive parents, other relatives or in an institution). Whether or not a child was infected did not influence the likelihood of living in alternative care. Maternal injecting drug use, single parenthood and health status were the major reasons necessitating alternative care. The type of alternative care varied according to maternal characteristics, child's age and geographic location. The mothers of 98 children had died and average age at maternal death was four years.