In our increasingly litigious society there is persistence of an attitude that posttraumatic headache (or other injuries) will either improve or disappear following resolution of a claim. In some states (Florida) in order for a person to initiate a claim, an injury must be considered permanent. This is often a difficult task with a subjective symptom. This retrospective study was performed to evaluate the reliability of criteria used to diagnose a "permanent" posttraumatic headache and whether these headaches stay "permanent" after legal settlement. Data was obtained by a structured telephone interview of fifty adult outpatients diagnosed as having permanent posttraumatic headache and their litigation settled at least one year previously. Patients with previous headaches, other accidents or head injuries were excluded. The average length of time from settlement to interview was 23 months. Forty-six had been in automobile accidents and four either had falls or blunt trauma to the head. (Eight cases involved Workman's Compensation). Criteria used at this clinic for determining permanency were either posttraumatic headache persisting for longer than one year with no evidence of further improvement (43 patients) or patients with headaches persisting longer than 6 months with a plateau (no change) in their pattern for three months or more with an adequate trial of treatment (in our judgement). These criteria did seem reliable. All fifty patients interviewed continued to report persistent headache symptoms one year or more following legal settlement. Improvement in headache pattern after legal settlement was only reported by four patients.