Supravalvular aortic stenosis may be defined as an obstructive congenital deformity of the ascending aorta which originates just distal to the level of the origins of the coronary arteries It may be localized or diffuse. Enlargement of the aorta with a diamond-shaped patch of the noncoronary sinus of Valsalva was reported in 1961 by McGoon and associates But this reconstruction is asymmetric and the aortic obstruction may remain. In 1977, Dotty and associates reported the extended aortoplasty, the supravalvular ring was incised at two points in the noncoronary and in the right coronary sinuses of Valsalva closed with a tubular Dacron prosthesis of inverted Y-shape tailored to reconstruct the aorta We experienced three cases of the supravalvular aortic stenosis. The 11-year-old female and 4-year-old male with localized supravalvular aortic stenosis in William`s syndrome were operated with an inverted Y-shaped aortotomy toward the non-coronary sinus and the right coronary sinus and closed with "Hemashield`s collagen impregnated Dacron" tube graft, fashioned into "pantaloon" form patch. The 12-year-old male with localized supravalvular aortic stenosis and mitral insufficiency in William`s syndrome were operated with same procedure as two other patient above-mentioned for relief of supravalvular aortic stenosis and with mitral valve replacement. Postoperative course has been good.ourse has been good.