Mitral valve prolapse is a common cardiac abnormality associated with arrhythmias and sudden death. In most instances it can be diagnosed on the basis of physical findings. Those patients who are symptomatic or who display electrocardiographic abnormalities appear to be most susceptible to arrhythmias and, therefore, may be at increased risk for anaesthesia. Because the syndrome is relatively common and may present a very innocent clinical picture, anaesthetists should be aware of this condition and the problems it may present. A case of mitral valve prolapse syndrome associated with ventricular fibrillation on induction of anaesthesia is reported. The symptoms and pathophysiology of the disorderare reviewed and the potential problems and the anaesthetic management are discussed. © 1979 Canadian Anesthesiologists.