Data on the age at death of children with congenital heart disease recorded 27 years before the introduction of cardiacsurgery on a territory where all deceased children were subjected to necropsy and data on the incidence of heart disease in the child population in Bohemia were used to calculate probable survival. Of liveborn infants with heart disease 90% surviev the first week, 86% the first month, 74% six month, 71% the first year and 67% 15 years. Pulmonary stenosis and a ventricular septal defect have the most favourable prognosis. The syndrome of a hypoplastic left heart, double outlow right ventricle, total anomalous pulmonary venous return, arterial truncus and pulmonary atresia have the most adverse prognosis.