Prenatal diagnosis of a congenital coronary artery fistula between the right coronary artery and right ventricle was made by two-dimensional and color Doppler echocardiography in a pregnant woman at 37 weeks of gestation. The right ventricle and right coronary artery were dilated with a fistula between them. A boy was delivered at 39 weeks gestation. Progression of the fistula was monitored by serial echocardiography postnatally. Because there were severe symptoms associated with the fistula, the infant had an operation 6 months after he was born. Four years of follow-up examination showed that the boy is in good clinical condition.