Double-chambered right ventricle [DCRV] is a rare congenital heart disease caused by anomalous muscle bundle traversing the sinus portion of the right ventricle well beneath the infundibulum. Recently we have experienced a case of DCRV with ventricular septal defect in 7-year old male patient. Preoperative cardiac catheterization and cineangiography revealed 80 mmHg pressure gradient between the proximal and distal chamber of the right ventricle and diagonal shape filling defect by the anomalous muscle bundle in the sinus portion of the right ventricle. Resection of the anomalous muscle bundle and patch closure of the ventricular septal defect was performed with cardiopulmonary bypass. The postoperative course was uneventful and excellent.