Several recent studies suggest that head injury may be a potentially useful factor in explaining some types of aggressive behavior. In our research, we have been able to demonstrate an association between head injury and marital aggression using a sample of male batterers and appropriate comparison groups. Anecdotal and empirical literature also supports the hypothesis that aggression, relationship problems, and negative changes in personality and behavior are common sequelae to a head injury. This article explores the hypothesis that flows intuitively from the above, namely, that head-injured males are at increased risk for physical aggression in their intimate relationships. Empirical data are presented identifying several risk factors for relationship aggression and marital discord that may be sequelae of a significant head injury. Nevertheless, head-injured men were not found to be more physically aggressive with their female partners. The implications of these results are discussed.