The purpose of the study was to investigate the differences between two types of onset (post-traumatic versus idiopathic) in pain, disability, and psychological distress in patients with fibromyalgia syndrome (FS). Forty-six FS patients with post-traumatic onset and 46 FM patients with idiopathic onset, who were matched in age and pain duration, were included in the study. All participants completed self-report inventories assessing their adaptation to the pain conditions, and during the medical examination, an examining physician completed an inventory (Medical Examination and Diagnostic Information Coding System; MEDICS) to indicate the degree of physical abnormality. The analysis revealed that the degrees of physical abnormality of the patients were comparable in the two groups. However, controlling for the involvement with financial compensation issues (e.g. disability, litigation), the post-traumatic FS patients reported significantly higher degrees of pain, disability, life interference, and affective distress as well as lower level of activity than did the idiopathic FS patients. Furthermore, evaluation of the treatment history in these patients revealed that a significantly larger number of the posttraumatic FS patients were receiving opioid medications and had been treated with nerve block, physical therapy, and TENS. The results suggest that (1) post-traumatic onset is associated with high level of difficulties in adaptation to chronic FS symptoms and (2) FS patients are a heterogeneous group of patients.