A 23-y-o male patient was suffered from intermittent fainting and dyspnea on exertion [NYHA Class IIIIV]. 2-D - Echocardiogram and cardiac catheterization with cineangiogram showed typical IHSS findings those were asymmetrical septal hypertrophy [ASH], systolic anterior motion of anterior mitral leaflet [SAM] which induced mild mitral regurgitation [Seller Grade I/IV] and pressure gradient about 60 mmHg between left ventricle and the aorta. Medical treatment with 8-adrenergic blockade [propranolol] and Ca" channel antagonist [Verapamil] had no response. So, we performed trans-aortic ventricular septal myotomy and mymectomy. Resected rectangular muscle bar was 1 Cm x 1 Cm x 4.5 Cm. Post-operative pressure gradient between the left ventricle and the aorta was less than 10 mmHg and SAM. was disappeared with decreased mitral regurgitation grade. Post-operative course was smooth and his symptoms and signs were free without any medication during 12 months follow-up.w-up.