Supravalvular aortic stenosis is a rare congenital cardiac anomaly occurring mainly as a part of Williams-Beuren syndrome. Aortic narrowing above the level of the aortic valve causes obstruction of the left ventricular outflow tract, and a pressure gradient between the left ventricle and the aorta causes left ventricle hypertrophy. We report here a case of a 22-year-old man who underwent extended patch aortoplasty because of supravalvular aortic stenosis accompanying Williams-Beuren syndrome. He was in New York Heart Association functional class III with localized hourglass type supravalvular aortic stenosis. Related to arterial hypertension he was in a cardiac decompensation. Mean pressure gradient was 73 mm Hg and maximum gradient 104 mm Hg. Electrocardiography indicated left ventricle hypertrophy, which was also seen in x-ray, as heart enlargement. We successfully treated this patient with extended patch aortoplasty and immediate postoperative echocardiography showed reduction of gradient. Good surgical outcome of congenital supravalvular aortic stenosis in adults can be achieved with this treatment. This technique provides symmetric reconstruction of the aorta with good postoperative results and no gradient across aortic valve and aortic valve insufficiency remains, providing excellent long-term relief of localized supravalvular gradients and preservation of aortic valve competence.