This follow-up study elucidates the incidence of criminality among brain injured persons. All the 1930 Finnish veterans who survived a penetrating brain injury during World War II were included in the study. The follow-up covered a period of 32-37 years. Five hundred randomly selected non-injured veterans of the same war were used as controls. A comparison of the frequency of convictions for crimes punishable by imprisonment among the injured and non-injured groups revealed no statistically significant difference between the two groups. This result shows, in accord with several reports on this subject published in the last two decades, that criminal behavior is not a sequela of injury to the brain.