To evaluate the prevalence and the characteristics of secondary trauma among patients referred to the emergency department (ED) for a transient loss of consciousness (TLOC). Over a 24 months period, all the patients referred to our ED for a TLOC were evaluated according to the ESC Guidelines on Syncope and enrolled in the study. Among 1253 consecutive patients with TLOC (1114 with a true syncope and 139 with a non-syncopal condition) 365 (29.1%) reported a trauma, in 59 cases (4.7%) severe. The frequency and the characteristics of trauma did not differ among the two main categories of TLOC. Out of 54 patients with syncope and a severe trauma, 20 (37%) had a definite diagnosis after a guidelines-based initial evaluation, and further 17 (31.5%) during the hospital course. Among these latter, carotid sinus syndrome was by far the most common diagnosis. Among patients referred to the ED for a TLOC secondary trauma is a common complication, whose characteristics are of little utility to discover the specific cause of the symptom. For older patients with syncope complicated by a severe trauma carotid sinus massage should be the first diagnostic manoeuvre to be undertaken after a non-diagnostic initial evaluation.