About 2 to 3% of births are associated with major congenital anomalies diagnosed at or soon after birth. Congenital malformations accounted for an estimated 495 000 deaths worldwide in 1997. The great majority of these deaths occurred during the first year of life, and thus tend to contribute mostly to the infant mortality rate. Because of the multiple factors involved, infant mortality attributable to congenital anomalies can be expected to vary substantially among countries. Children with congenital anomalies who survive the high-risk period during the first year of life still have low survival rates as children and adults. The leading causes of infant morbidity and mortality in poorer countries are malnutrition and infections, whereas in developed countries they are accidents and congenital malformations. With the control of infectious diseases and malnutrition, particularly in developed countries, congenital anomalies are now making a proportionally greater contribution to ill health in childhood.