In order to investigate the morbidity and mortality in individuals with Down syndrome(DS), we reviewed 237 cases of DS visiting our hospital in a ten-year period. There were 150 males and 87 females with age range from newborn to 25 years. The major illnesses included: 1) congenital heart disease (CHD), 42.6%; with endocardial cushion defect, ventricular septal defect, atrial septal defect and patent ductus arteriosus as the common types; 2) frequent or major respiratory tract infections, 34.2%; 3) summer fever, 5.5%; 4) major infective episodes other than pneumonia, 5.0%. Other diseases such as seizure disorder, gastrointestinal tract anomalies and thyroid dysfunction were also noted. There were 28 deaths of them and the causes of mortality were 1) CHD with congestive heart failure (CHD with CHF) and pneumonia (46.9%); 2) CHD with CHF and sepsis (10.7%); 3) CHD with CHF (14.3%) and 4) acute leukemia with infection (10.7%) respectively. Most of the mortality occurred during the first year of life, especially in patients with CHD. In our series, the one year survival rate was 93.6%; the result indicates that life expectancy in DS is much better than generally believed.