This chapter describes mitral valve lesions: mitral valve stenosis is rare as an isolated defect, with clinical symptoms dependent on the degree of stenosis. Mild stenosis is asymptomatic, moderate to severe stenosis presents with dyspnoea due to pulmonary hypertension and right heart failure. Tachycardia should be avoided and inotropes might be needed for impaired function. Mitral valve regurgitation or prolapse is rare as a islolated defect. 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.