Congenital coronary arteriovenous aneurysm with anomalous drainage into the coronary sinus, the right atrium, the right ventricle, or the pulmonary artery is a rare malformation. The authors found 16 cases reported in the literature, 6 of which occurred in patients under 16 years of age. Of these 16 patients, 3 with a preoperative diagnosis of patent ductus arteriosus were successfully operated on. One of these three patients was operated on at Cook County Hospital, and the case was reported inThe Journal.1 We wish to report an additional three cases with an aneurysmally dilated right coronary artery draining into the right ventricle. Report of Cases Case 1. —The case of a noncyanotic 7-month-old male infant was diagnosed clinically as one of arteriovenous coronary aneurysm. This diagnosis was confirmed by venous angiocardiography and cardiac catheterization. Corrective surgery was successfully accomplished. Case 2. —The case of a 5-year-old boy was diagnosed