Racial group studies have identified differences in the occurrence of congenital heart disease (CHD) among ethnic populations. The aim of this study was to characterize the proportionate frequency and clinical profile of children with symptomatic cardiac abnormalities in Hong Kong. The hospital records of 666, mainly Southern Chinese children with symptomatic CHD, who were 4 years of age or younger and who were admitted to Grantham Hospital, Hong Kong, in 1994 and 1995 were analyzed retrospectively. Left-to-right shunting (45.0%) and pulmonary outflow obstruction (34.4%) were the most frequently diagnosed categories, followed by left ventricular outflow obstruction (8.3%), transposition of the great arteries (4.2%), conditions with intracardiac mixing (3.9%), and other cardiac lesions (4.2%). Compared with Western studies, pulmonary outflow obstruction (p<0.0001), particularly tetralogy of Fallot and critical pulmonary stenosis, were more frequent in Chinese children. In contrast with previous reports, coarctation of the aorta (5%) does not seem to be uncommon in Chinese patients. Conversely, aortic stenosis and hypoplastic left ventricle may be rare in these children (1% vs 3% and 3-7%). Other cardiac lesions showed no consistent racial difference in the frequency of occurrence. Chinese patients with Down's syndrome had ventricular septal defect (38%) as the predominant lesion followed by atrioventricular septal defect (25%). Western studies usually report a reverse pattern for these two lesions. The mortality rate for the total cohort was 7.5%. However, of those with conditions with intracardiac mixing and left ventricular outflow tract obstruction many did not survive childhood (20% and 21%, respectively).