If radical correction of congenital heart disease can be performed with a low risk in the first year of life the advantages are obvious. Total correction avoids the latent risks of the underlying lesion and the risks of palliative surgery, and relieves the parents and family of the psychological pressure of a major illness. Palliative surgery, although offering survival, may include the long term problems of the palliative operation itself, and the possibility that cases may be lost to further treatment or follow-up examination after a successful palliative operation. For these reasons, to be desirable, a palliative operation should offer a survival chance that is at least 10% better than the corrective procedure in that patient at that time. That is, any corrective procedure with a mortality rate less than 10% is to be perferred at any age to a palliative operation. An accurate assessment of risk demands a complete diagnostic study, and a knowledge of the natural history of that form of congenital heart disease. The problems of infants with congenital heart disease are not primarily caused by age of size. The main problem is that of natural selection.