Subaortic stenosis (SAS) is a consequence of left ventricular outflow tract obstruction (LVOTO). Secondary subaortic stenosis (SSS) can occur after surgery for various congenital heart defects with or without initial LVOTO. Surgical repair, irrespective of gradient, is advised to reduce the damage to aortic valve. Adequate resection of SAS reduces the risk of endocarditis. Aggressive myectomy with membrane resection yields good results in discrete SAS. We report a patient with SSS which was arised after surgery of congenital heart defect. He had a history of a patch closure operation of subarterial ventricular septal defect(VSD) at four months after birth. After operation, there were no leakage of previous VSD and LVOTO in echocardiogram. After 3 years of surgery, He had fever and coughing, so we checked echocardiogram. He had LVOTO and it revealed subaortic stenosis with subaortic membrane. We consulted to thoracicsurgery for surgical remove of subaortic membrane. He will be closely monitored of peak transvalvular pressure gradient, aortic regurgitation, and aortic insufficiency by echocardiogram. If those parameter increases, surgical removal of subaortic membrane will done.