In 1983, 290 patients with congenital heart disease (CHD) underwent surgery at our institute. Among them, 36 (12%) had no preoperative catheterization or angiography. These 36 patients were categorized as group I consisting of 12 patients less than two months of age and group II consisting of 18 patients more than one year of age. The diagnosis was accurate in 34 of the 36 patients (94%). Assessment by two-dimensional echocardiography (2-DE) was incomplete for two patients. A secundum atrial septal defect in one patient diagnosed by 2-DE, proved at surgery to be a sinus venosus type atrial septal defect with partial anomalous pulmonary venous drainage. Another patient was diagnosed as having tetralogy of Fallot with the absent pulmonary valve by 2-DE, but anomalous origin of the right pulmonary artery from the ascending aorta was also found at surgery. There were 25 operations in patients less than two months of age, and 12 (48%) of them had surgery without catheterization (Group I). Most patients in Group I were less than two weeks of age (nine patients) and six of these were operated without catheterization (pure pulmonary atresia: 2, total anomalous pulmonary venous drainage: 2, interruption of the aorta: 1, tetralogy of Fallot with absent pulmonary valve: 1). Another two cases had surgery after only radial artery retrograde aortic arch visualization, then, preoperative intracardiac catheterization was avoided in eight (89%) of the nine patients. Atrial septal defect (ASD) and patent ductus arteriosus (PDA) patients, 25% and 69% of the cases, respectively, were operated on without catheterization. In conclusion, we can better maintain the general condition of critically-ill neonates and infants in surgery, when prompt and accurate 2-DE diagnoses are made for typical cases without catheterization and angiography. In older children of uncomplicated ASD or PDA with typical physical findings, we can avoid catheterization before surgery. If, however, information is insufficient for deciding surgery, we should carry out invasive examinations without hesitation.