Syncope is a common symptom in emergency department visits and, despite extensive evaluation, still remains un- explained in a significant number of cases. Our study com- pared the clinical characteristics of patients with syncope of unexplained aetiology (SUA) with those of patients with other causes of syncope after the application of a stan- dardised work-up. Recurrence and death rates were also evaluated at one year. We found that patients with SUA shared most of the clinical and paraclinical characteristics of patients with neurally mediated syncope. During follow- up, recurrences occurred essentially in the SUA group. These findings support the concept that patients with SUA suffer from some form of neurally mediated syncope.