A 63-year-old female with Marfan syndrome had undergone an initial operation of replacement of the ascending aorta and aortic valve with a composite graft and reconstruction of the coronary artery by the Cabrol procedure for aortic root dilatation and aortic valve regurgitation. During a follow-up of 16 years, a decreased ejection fraction was observed on transthoracic echocardiography with the onset of chest pain and dyspnea. Computer tomography angiography revealed a prostheto-prosthetic pseudoaneurysm, initially measured 21x16x23 mm, rapidly increased at 1-year follow-up at 27x24x33 mm. Coronary angiography showed the presence of turbulent flow inside the pseudoaneurysm with a decreased coronary perfusion. We resected the pseudoaneurysm and a new prostheto-prosthetic anastomosis was performed. The postoperative course was uneventful without any complications. We report this case because in literature there has been few reports regarding prostheto-prosthetic pseudoaneurysm after Cabrol procedure.