Nonbacterial thrombotic endocarditis is characterized by the presence of valve-leaflet or endocardial vegetation composed chiefly of fibrin and trapped platelets, without an associated inflammatory reaction or evidence of microorganism. Recent emphasis has been affixed to the significant morbidity and mortality rates as a results of major systemic arterial embolization and infective endocarditis. It is seen most commonly in patients with malignant neoplasms, disseminated intravascular coagulopathy, uremia, burn, SLE, cardiac valve disease. We experienced a case of nonbacterial thrombotic endocarditis developed in patient with small congenital ventricular septal defect, and vegetation on the left ventricular septum other than right ventricle as known most commonly affected.