Atresia of the ostium of the coronary sinus (CS) is a well-recognized abnormality., We, report the incidental finding of atresia of the distal portion of the CS, a short distance proximal to its ostium in a 39-week-old neonate, which, as far, as we are aware, has not been previously reported. (C) 2004 Elsevier Inc, All rights reserved.