The aim of the study was to evaluate the effect of patient age on the clinical presentation of syncope and to establish the diagnostic value of clinical history in older patients. A total of 485 consecutive patients with unexplained syncope referred to secondary and tertiary hospitals were divided into 2 predefined age groups: 224 patients <65 years and 261 patients > or =65 years. The diagnostic criteria for the cause of syncope were developed before the beginning of the study. The clinical features of syncope were analyzed using a standard 46-item form. A cardiac cause of syncope was established in 27 younger (12%) and 89 older (34%) patients. A neurally mediated cause was established in 154 younger (68%) and 142 older (54%) patients. In patients > or =65 years, the clinical features of cardiac and neurally mediated syncope were very similar. The diagnosis of the cause of syncope was possible on the basis of the history alone in 26% younger and 5% older patients (p <0.0001). Myoclonic movements, effort syncope, and supine position during loss of consciousness were the most specific (97%, 99%, and 99%, respectively) diagnostic criteria for a cardiac cause of syncope in older patients, but, all together, they accounted for only 14% of patients. In conclusion, compared with younger patients, the medical history has a limited value in the diagnosis of the cause of syncope in older patients. The specificity of some features is high but these can be observed in only a minority of patients.