In the 27 years from 1952 to 1979 (before the introduction of advanced cardiac surgery) all children in Central Bohemia (population 1.2 million) who died before the age of 15 were examined at necropsy. Period death rates at various ages were calculated in those with congenital heart disease. Nearly all the deaths (848, 89.6%) occurred in the first year. Forty three (44% of survivors) died in the second year and 17 (31% of survivors) died between the second and fifth years. Over half (20) of the survivors died between the fifth and tenth years. Nearly half (44.2%) of those born with congenital heart disease who died before the age of 15 died in the first four weeks. About a third (29.1%) died in the first week and period death rates were 9.7%, 7.6%, and 5.7% for the second, third, and fourth weeks respectively. In neonates death rates were highest in those with hypoplastic left heart syndrome (89.2%), coarctation of the aorta (66.7%), truncus arteriosus (61.8%), double outlet right ventricle (57.1%), and pulmonary atresia (56.3%).