A case of straddling tricuspid valve associated with dextrocardia and VSD was presented. Closure of ventricular septal defect and tricuspid valve replacement were performed on this patient. Since the straddling septal leaflet of the tricuspid valve shared a posterior papillary muscle in the left ventricle with the posterior mitral leaflet, division of this papillary muscle was thought to induce papillary muscle dysfunction of both leaflet. Hence, the chordae of straddling tricuspid leaflet was detached from the shared papillary muscle and the ventricular septal defect was closed by a large pericardial patch. Because of peculiar anatomy of the conduction system in this situation, the junctional area of the inlet septum and tricuspid annulus was avoided from stitching in VSD closure. Suture through the tricuspid septal leaflet and pericardial patch for VSD were used for tricuspid valve replacement as well. The patient showed uneventful postoperative course without any conduction disturbance including the right bundle branch block.