Endoscopic vein harvesting (EVH) for coronary artery bypass grafting (CABG) has gained increasing acceptance as a less invasive altative to conventional open vein harvesting. With this procedure, carbon dioxide (CO2) is insufflated to create a subcutaneous tunnel to facilitate the harvest of the great saphenous vein. The technique seems to be safe because there are no adverse hemodynamic consequences or systemic CO2 absorption during EVH.1,2 We report a case of massive right heart gas embolism which occurred during a routine EVH performance of the saphenous vein.