A case of a single coronary artery complicated with a coronary artery fistula (CAF) to the right ventricle is extremely rare, and its management strategy and prognosis are not clear. A 5-year-old boy was hospitalized for evaluation of a continuous heart murmur. Transthoracic echocardiography suggested a CAF to the right ventricle, with an enlarged left coronary artery. Cardiac catheterization confirmed the CAF terminating at the right ventricle and the absence of a right coronary artery. The fistula was ligated at the right ventricular side under cardiopulmonary bypass. At follow-up 18 months later, the child was clinically asymptomatic, and coronary angiogram showed no recurrence of the fistula.