Six cases of congenital coronary arteriovenous fistulae were diagnosed radiographically and confirmed after operation at Seoul National University Hospital in recent three and a quarter years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 6 cases, 2 cases were male and 4 cases were female. Age distribution was from 3 months to 19 years. 2. In chest X-ray findings, 5 cases had cardiomegaly. Among these 5 cases, increase of pulmonary vascularity was in 3 cases. Chest X-ray finding of the rest 1 case was within normal limit. 3. The coronary arteriovenous fistula orginated from the right coronary artery in 5 cases and from the single left coronary artery in 2 case. In 5 cases, a coronary arteriovenous fistula drained into the right ventricle and in 1 case, a fistula from a SA node branch of the right coronary artery into the right atrium. 4. In 5 cases, a main right coronary artery was dilated. Among these 5 cases, aneurysmal dilatation of main right coronary artery was in 2 cases, saccular aneurysmal dilatation of distal portion of right coronary artery was in 2 cases and in 1 case, diffuse dilatation without aneurysm formation of a main right coronary artery. In 1 case, SA node branch of the right coronary artery was dilated with aneurysm formation. 5. For accurate diagnosis of congenital coronary arteriovenous fistula, biplane cinecardiography is an essential procedure.