The pathophysiology and therapy of the carotid sinus syncope were studied by means of electrophysiological investigations and clinical observations in 84 patients suffering from carotid sinus syncope. The most important data and conclusions of the study are the following: 1. The most frequent cause of the carotid sinus syncope (Adams-Stokes) attack is the sinus arrest and a sinus block. 2 degrees-3 degrees av block can be observed less frequent in the course of syncope attack. 2. In a patient suffering from carotid sinus syncopes, disorders of impulse formation and impulse conduction of the heart are frequent. First of all, the association of the sick sinus syndrome and the carotid sinus syncope can be often detected. 3. It is not rare at all that the carotid sinus syncope occurs with extracranial obliterative disorders. Transitory cerebral ischaemic attack frequently develops on the stimulation of the carotid sinus area. 4. The drug -- atropine -- therapy of the carotid sinus syncope is usually insufficient. Generally, pacemaker implantation is the adequate treatment. Late results are very good after pacemaker implantation.