Quadricuspid aortic valves (QAVs) are a rare but well-recognized congenital heart disease and a cause of aortic regurgitation. The first case was reported in 1862. Since then, there have been about 189 cases reported with advances in echocardiography, more cases are diagnosed by transesophageal echocardiography. Hurwitz and Roberts have classified QAV according to the size of the leaflets. Our case demonstrates 2 different valve classifications based on equal and unequal cusp size. In conclusion, to our knowledge, this is the first case of QAV in identical twins.