The reduced risk of mother-to-child transmission due to improved HIV treatment has resulted in an increasing number of healthy children born to mothers living with HIV. The study's objective was to identify the number of parents or caregivers in a sample of persons living with HIV in Flanders, the number of HIV-affected children as well as specific family-related characteristics. Using a structured survey quantitative data were assessed on a total of 628 patients at three Flemish Aids reference centres. Qualitative data were collected in a small sub-sample of African caregivers living in Flanders. Twenty-seven per cent of the overall sample had children younger than 18 years, totalling 165 HIV-affected families with 279 children. Parents from developing countries had significantly more children than European parents. One hundred and eighty-two (68%) of all children were HIV-negative, while the HIV status of 75 (28%) was unknown. Disclosure rate was low: 26 (10%) children were aware of the parental HIV disease. The study shows that HIV-affected families have to deal with complex psychosocial issues such as migration, family illness, family secrecy around HIV and disclosure. Service implications are discussed.