The diagnostic accuracy of echocardiography alone and the safety of cardiac surgery using this diagnostic approach were retrospectively assessed in 111 children operated for congenital heart defects (CHD) during a 3.5-yr period ending in October 2001. Preoperative diagnosis was compared with the intraoperative findings obtained by surgical inspection. Perioperative death was defined as death within 30 days postoperatively. Of the patients, 70% were operated on in infancy. Seventy-six percent (84 of 111) underwent surgery after echocardiographic diagnosis alone. A high percentage of patients with patent ductus arteriosus (100%), partial atrioventricular canal (100%), coarctation of the aorta (89%), ventricular septal defect (86%), atrial septal defect (85%), and total anomalous pulmonary venous connection (75%) was operated without prior catheterization. Diagnostic errors occurred in 2.4% (2 of 84) of patients with echocardiography only and in 7.4% of patients with catheterization. No error in either group was related to surgical morbidity or mortality. There were five (6.0%) perioperative deaths in the echocardiography group and two (7.4%) in the catheterization group, with no difference in the mortality between the groups. In conclusion, many patients with CHD can be accurately diagnosed by echocardiography alone, and can safely undergo surgery without catheterization, not increasing the overall risk.