This chapter describes aortic valve lesions. Aortic stenosis can be congenital or acquired, with clinical symptoms dependent on the degree of stenosis. Mild stenosis is asymptomatic, moderate to severe stenosis causes high ventricular pressures with low cardiac output syndrome. Anaesthetic management aims to avoid tachycardia while maintaining adequate blood pressure for coronary perfusion. Inotropes might be needed, depending on ventricular function. Aortic regurgitation is rare as an isolated lesion. Symptoms depend on severity of regurgitation and associated lesions. Anaesthetic management aims to promote forward flow by carefully reducing systemic vascular resistance while maintaining coronary perfusion pressures and to avoid bradycardia.