Quadricuspid aortic valve (QAV) is a rare cause of aortic regurgitation. Most cases are detected incidentally during echocardiography, angiography, autopsy or surgery. It may also be associated with other congenital anomalies of the heart. A 70 year-old man was admitted to our hospital with a five-month history of dyspnea. Echocardiographic examination showed a QAV leading to moderate aortic regurgitation, severe mitral regurgitation, left ventricular dysfunction and aortic root dilatation. Surgical treatment was considered, but the patient refused. We describe a case of QAV leading to aortic regurgitation.