Introduction: Mild traumatic brain injury (MTBI) is common, difficult to manage, and its long-term consequences are poorly understood. A prospective study was conducted at the Annecy Regional Hospital Center (CHRA) to estimate the prevalence of symptoms at 6 months and to identify factors associated with their occurrence. Methods: All patients who presented to the CHRA emergency department between February 2006 and July 2007 with a mild TBI were contacted by telephone six months after the injury to screen for persistent symptoms. Patients who reported symptoms during the telephone call were referred for a consultation at the department’s resource center for people with brain injuries. Results: Among the 795 patients contacted, 93 reported symptoms: memory problems (80%), fatigue (79%), headaches (65%), irritability (64%), language difficulties (64%), and attention problems (62%). After adjustment, the presence of symptoms at 6 months was associated with age, being female, having reported headaches during the initial emergency department examination, and having undergone a CT scan. Discussion: The symptoms reported by CHRA patients were consistent with those reported in other studies on the subject. These symptoms are often nonspecific, and to demonstrate their association with head injury, a case-control or exposed-unexposed study would be more appropriate. (R.A.)