Tetralogy of Fallot is the most common cyanotic congenital heart disease in children and is not difficult indiagnosis on the clinical and conventional radiographical ground. However, with these diagnostic methods, correctdiagnosis of internal morphological anomalies cannot be made. Angiocardiography is the only method for thediagnosis of internal anomalies and their severity in Tetralogy of Fallot, and for the differenciation fromTetralogy-simulating congenital cardiac anomaly. With recent advances in cardiac surgery, it is possible toperform total corrective surgery satisfactorily, and this in turm make angiocardiography and essential procedurein the diagnosis of Tetralogy of Fallot. Seventy cases of Tetralogy of Fallot diagnosed angiographically from 1971to 1975 in Seoul National University Hospital were reviewed and compared with operative findings. The results areas follows; 1. Right ventriculography is the best method in the diagnosis of morphological anomalies of Tetralogyof Fallot, and findings are correlated well with operative results. 2. Angiocardiography is the only method forthe diagnosis of Tetralogy-simulating congenital heart disease, such as double outlet right ventricle withpulmonary stenosis and transpostion complexes with pulmonary stenosis. 3. Angiocardiographic findings are valuablein the selection of good candidate for total correction of Tetralogy of Fallot.