A descriptive epidemiologic study of head injury cases that were discharged from army medical facilities during fiscal year 1983 was performed. For the diagnosis of concussion, the male and female rates were approximately equal between the ages 18–24 and 25–34 and for the total, ages 18–34. For the diagnosis of other- intracranial injury and the total of all head injuries, males between ages 18–24 and 18–34 had statistically significantly higher rates than females. Cases were reviewed from Walter Reed Army Medical Center to test the hypothesis that alcohol and drug abuse were underreported risk factors for military personnel sustaining head