Despite successful surgical repair, patients with congenital aortico-left ventricular tunnel (ALVT) are at risk of developing aortic incompetence in the late postoperative period. Two cases of ALVT were followed for 10 years with special reference to aortic incompetence and geometry of the aortic root. The patients underwent repair of ALVT, one at 4 years of age and the other at 4 months of age. The first patient had a slit-like tunnel (type I) and the aortic orifice was closed with a pericardial patch. The second patient had a large tunnel with an extracardiac aneurysm (type II) and was closed with a pericardial patch at the aortic orifice and a Dacron patch at the left ventricular orifice, thereby completely obliterating the tunnel. The last echocardiographic evaluation showed no residual flow in the tunnel and no aortic incompetence in case 1, but there was mild aortic valvular regurgitation with deformity of the right sinus in case 2. Careful long-term follow-up is necessary because patients with ALVT have some inherent structural abnormalities from the left ventricular outflow tract to the aortic root. (Circ J 2006; 70: 939 - 941)