We surveyed the incidence of congenital heart disease in 49887 native live born children in the period between 1984 to 1994 in Qatar. Each child with clinically suspected congenital heart disease underwent echocardiographic examination. Magnetic resonance imaging, cardiac catheterization and surgical intervention were done at the discretion of the patient's pediatric cardiologist. Virtually no postmortem examinations were performed. Children with congenital heart disease were entered into a computerized database and were then followed for 1-11 years. Congenital heart disease was diagnosed in 610 of 49,887 children for an incidence of 12.23/1000 live births. The reasons for the high incidence were high proportion of small muscular ventricular septal defects discovered before the time of their spontaneous closure, referral to and follow up by a single group of pediatric cardiologists, location of the pediatric cardiology service in the same setting where nearly all of the deliveries took place, freely available health care service, and echocardiographic examination of every child with a clinical diagnosis of congenital heart disease.