This study sought to determine whether chronic post-traumatic headaches are different from or identical to the naturally occurring headaches. The chronic post-traumatic headaches of 48 patients were classified, as if they were natural headaches, by the diagnostic criteria of the International Headache Society. Thirty-six patients’ headaches (75%) were chronic tension-type headache, 10 (21%) were migraine without aura, and 2 (4%) were unclassifiable. The characteristics and accompaniments of the headaches within each diagnostic group were then compared to those in a control group with natural headaches of the same type. No notable differences between the post-traumatic and control groups were found. Hence, chronic post-traumatic headaches have no special features, but are symptomatically identical to either chronic tension-type headache or migraine without aura (in this series of patients). This identity suggests that post-traumatic headaches are generated by the same processes causing the natural headaches, not by intracranial derangement from head blows or jolts.