In two investigations, 50% of non-violent convicted felons, who avoided incarceration by participating in a day reporting programme, reported a prior history of head injury and current problems in cognitive and emotional functioning. Only 5% of a college sample in the first investigation and 15% of a community sample in the second investigation reported prior head injury. In a third investigation, 83% of felons who had reported a history of head injury also reported a date for their head injury that preceded the date of their first encounter with law enforcement. Some participants reported no trouble with the law until after experiencing a head injury that occurred in their late thirties. Considering the research reported here and elsewhere in the literature, it appears that many serious crimes follow a head injury. One implication of the findings reported here is that many crimes might not occur if people with head injury were given prompt and comprehensive treatment after the injury.