THE CORONARY artery distribution in tetralogy of Fallot is important from the standpoint of (1) the site to choose for the ventriculotomy, (2) the presence of anomalous vessels at the ventriculotomy site, and (3) the effects upon the myocardium of section of an important vessel. The general distribution of the coronary arteries in all types of transposition complexes were discussed by Spitzer1 and reiterated by Lev.2 Longenecker et al3 studied the coronary arteries in 22 cases of tetralogy by dissection and injection. They found that the right ventricle was more vascularized than normal but the overall distribution was normal in 21 of 22 cases. In one case the left coronary emerged between the aorta and pulmonary trunk, coursed in front of the pulmonary trunk and passed deep into the myocardium. Senning4 observed at operation five cases of anomalous coronary artery out of 27 patients with tetralogy.