A rare case of aortic and mitral valve aneurysms complicated with infective endocarditis was accurately diagnosed by transesophageal echocardiography. A 57-year-old man with severe aortic regurgitation due to infective endocarditis was admitted to our hospital. Transthoracic echocardiography showed an aortic valve aneurysm on the right coronary cusp and perforations on the other cusps. Transesophageal echocardiography demonstrated a small aneurysm on the anterior leaflet of the mitral valve which was not clearly visualized by transthoracic echocardiography. Color Doppler echocardiography revealed severe aortic regurgitation and mild mitral regurgitation without perforation of the mitral valve aneurysm. Aortic valve replacement and mitral valvuloplasty of the anterior mitral leaflet were performed. The right coronary cusp of the aortic valve showed marked thinning with infiltration of inflammatory cells. The postoperative clinical course was uneventful.