The bicuspid aortic valve is a common congenital cardiac anomaly, having an incidence in the general population of 0.9% to 2.0% and a frequency of 54% in all patients aged >15 years with valvular aortic stenosis. In most cases it remains undetected until infective endocarditis or calcification supervenes. The bicuspid aortic valve may function normally throughout life, may develop progressive calcification and stenosis or may develop regurgitation with or without infection. The association of the bicuspid aortic valve with dissection of the aorta is also common. The recognition of the bicuspid valve in patients with aortic valve disease remains an important challenge to the clinician, whereas preoperative knowledge of valve morphology would be helpful in planning the surgery. Antibiotic prophylaxis is also recommended in such patients, since these valves are likely to become the most important intrinsic cardiac predisposition for infective endocarditis with the virtual disappearance of rheumatic fever in developed countries.