The symptoms of postconcussion syndrome (PCS) are persistent, and no empirically tested treatment is available. The treatment group ( n = 29) in this study received a printed manual and met with a therapist prior to hospital discharge to review the nature and incidence of expected symptoms, the cognitive-behavioral model of symptom maintenance and treatment, techniques for reducing symptoms, and instructions for gradual resumption of premorbid activities. The control group ( n = 29) received routine hospital treatment and discharge instructions. Both groups had sustained mild head injuries characterized by Glascow Coma Scale scores of 13–15 on admission without any measurable period of posttraumatic amnesia. Group assignment was random. Groups did not differ significantly on age, Glascow scores, litigation status, gender, or initial number of PCS symptoms. Patients were contacted 6 months following injury by an interviewer who was unaware of group assignment to obtain outcome data. Treated patients reported significantly shorter average symptom duration (33 vs. 51 days) and significantly fewer of the 12 symptoms at followup (1.6 vs. 3.1). Subjects were also asked how often each symptom had occurred in the previous week, and how severe the symptom typically was. The treatment group experienced significantly fewer symptomatic days (.5 vs. 1.3) and lower mean severity levels. Results suggest that brief, early psychological intervention can reduce the incidence of PCS.