The spectrum of patients operated on without preoperative catheterization and angiography, the accuracy of echocardiographic diagnosis and its impact on the results of surgical treatment were prospectively assessed in 2,788 children consecutively operated for congenital heart defects (CHD) between 1986 and 1992. The overall percentage of surgery based solely on noninvasive preoperative examination increased from 63% in 1986 to 81% in 1990 and decreased to 72% in 1992. There were no differences in the preoperative diagnostic approach between groups of newborn, infants and children. A high percentage of patients with patent ductus arteriosus (96.5%), atrial septal defect (94%), incomplete atrioventricular septal defect (88.6%), ventricular septal defect (86.3%), coarctation of the aorta (80.2%) and total anomalous pulmonary venous connection (79.3%) was referred for surgery without prior invasive examination, while a lower percentage was found in univentricular heart (48.4%), pulmonary atresia (34.6%) and double outlet right ventricle (27.7%). More patients with pulmonary and tricuspid atresia were catheterized before complete repair compared to those who underwent palliative surgery (p < 0.01 and p < 0.0001, respectively). The echocardiographic diagnosis was correct in 96% of patients. Two patients of those with incomplete preoperative diagnosis died early postoperatively, both with missed apical ventricular septal defect. One with tetralogy of Fallot died after reoperation, the other with persistent truncus arteriosus due to sepsis. When the echocardiographic findings are in full agreement with the clinical status, physical examination, ECG and chest X-ray, we recommend cardiac surgery without prior catheterization in many patients with CHD.