Syncope and autonomic failure are defined. Then the symptoms are described. There are three types of neurally mediated syncope; situational, carotid sinus hypersensitivity, and vasovagal syncope, which is the commonest form. The diagnosis can most often be made by taking a detailed history, but the tilt table test will help to confirm this. Details of the test are given. The different terms that have been used to describe this form of syncope have caused confusion, but neurally mediated syncope seems to be the best. There may often be difficulties in differentiating neurally mediated syncope from epilepsy, with all the problems a wrong diagnosis may cause, both personal and social, especially in the case of reflex anoxic seizures. The ocular compression test can help in making a definite diagnosis. Management will include reassurance, and advice on avoiding situations, which may result in an attack. Drugs are of limited value, and if syncope occurs frequently, cardiac pacemakers may have to be considered. This is justified, not only by the distress the attacks can cause to the individual, but also by such problems as driving and working with machinery.