Unicommissural unicuspid aortic valve (UAV) is a rare valvular malformation. It may lead to severe aortic stenosis with or without aortic regurgitation. UAVs have many characteristic changes such as premature dysmorphic valvular calcification and premature valvular dysfunction. Transesophageal echocardiography (TEE) was described as the gold standard for the diagnosis of UAVs. We reported the case of a 58 years old man who presented with syncope and dyspnea due to severe aortic stenosis secondary to a heavily calcified unicommissural UAV. After the surgery pathological specimen showed severe amorphous calcification just like a calcified amorphous tumor (CAT).