The present study investigated the possible role of a number of pre- peri-, and post-traumatic factors in the experience of post-concussion syndrome (PCS). These factors included: (1) history of premorbid risk factors, (2) severity of injury, and (3) post-morbid functioning and environmental factors. Subjects were 55 persons with mild brain injury. PCS was defined in terms of the severity and impact of 'late-onset' symptoms. Pre- and peri-traumatic factors were not associated with level of PCS symptom impact. Among post-traumatic factors, only level of psychological distress was strongly associated with impact level. The results suggest the importance of psychological factors in prolonged PCS.