A 4-year-old boy admitted to our hospital due to congestive heart failure one year after the intracardiac repair of tetralogy of Fallot. Echocardiography and cineangiography revealed severe aortic regurgitation. The aortic valve replacement was performed with a prosthesis larger than the aortic annulus. Operative findings showed that the cause of aortic regurgitation was infective endocarditis. The aortic root was enlarged with pericardial patch and a 21 mm St. Jude Medical valve prosthesis was inserted in supraannular position. This technique was very useful for insertion of a prosthetic valve one or two sizes larger than the aortic annulus without risk of distorting the mitral valve or left ventricular function.