We present the aims, methodology and initial results from the Italian Multicentric Study for the registration and follow-up of congenital heart disease. The general aims are to measure the prevalence of congenital heart disease in different geographic areas of Italy, and to assess the survival and outcome of affected babies. During the years 1992 and 1993, eighteen centers for Pediatric Cardiology spread all over the Country enrolled 1445 new babies with congenital cardiac malformations from a population of 341,647 surveyed livebirths. The new cases were registered using the same methodologic criteria of the EUROCAT study in order to evaluate differences and/or similarities between the studies. The prevalence varied between 1.8% and 8.1%; the average being 4.6%. The large range in prevalence is presumed to be related to different customs and hierarchies in flow and referral of patients. We provide total prevalence of individual lesions, and distribution of sentinel cardiac anomalies, in the Italian study and compare them with EUROCAT. Isolated ventricular septal defect is the most common lesion (39%); followed by atrial septal defect (7.5%); pulmonary valvar stenosis (7.3%); atrioventricular septal defects (5.4%); patency of the arterial duct (3.8%); complete transposition (3.7%); tetralogy of Fallot (3.3%); aortic coarctation (2.4%); aortic valvar stenosis (2.2%); and left heart hypoplasia (1.8%). The echographic stratification of ventricular and atrial septal defects, by location and size, was in keeping with the findings of the EUROCAT study. Because of the recent widespread availability of color-Doppler techniques, the stratification of aortic and pulmonary valvar stenosis was an innovative approach in our study. Among the complex cardiovascular anomalies, double inlet ventricle and pulmonary atresia had a proportion of about 2% each; with double outlet right ventricle, common arterial trunk, Ebstein's malformation, tricuspid atresia, interrupted aortic arch and totally anomalous pulmonary venous connection having a proportion ranging from 0.5 to 0.8%. We discuss clinical features, such as frequency of extracardiac anomalies and familial aggregation of congenital heart disease, in comparison with the EUROCAT data.