A survey conducted by cardiologists in Soweto, Johannesburg, provided an opportunity of assessing the frequency of congenital heart disease in black schoolchildren. Among 12,050 schoolchildren aged 2 to 18 years, 48 had a congenital heart defect, yielding a prevalence of 3.9 per 1000. Only in 2- to 6-year-old children did the prevalence exceed that of rheumatic heart disease. The distribution of the types of defects was largely similar to that reported in other surveys with a predominance (52%) of ventricular septal defects. Two unusual findings were the unexplained absence of persistent ductus arteriosus in these children, and the detection of 5 children with situs inversus (1 in 2410). In all but one child, the congenital heart defect was first discovered during the survey. Despite the limitations of a prevalence study, it can be concluded that congenital heart disease is at least as common in this South African black community as in Caucasians.