Clinical characteristics were studied in patients with chronic muscle pain, divided into three groups according to the characteristics of their pain; "fibromyalgia" (n = 23), "widespread muscle pain" (n = 21), and "regional muscle pain" (n = 28). Typical fibromyalgia features were also seen in the other groups of patients, but not to the same extent. In particular, sleep disturbance, subjective swelling, cold and exercise intolerance and low self-reported physical performance were significantly related to fibromyalgia. The major components of fibromyalgia were not wholly different compared with other European and North American studies, except for sleep disturbance and subjective swelling, which was somewhat more pronounced in this study. The most used medications in fibromyalgia patients at referral were analgesics, anxiolytic drugs and female sex hormones. Medication in fibromyalgia was not excessive and seemed appropriate compared to the other patient groups. Effects of various biases and classification criteria on the results of fibromyalgia studies are discussed. The characteristic features of fibromyalgia, its stability when diagnosed and the promotion of research and patient management justify the current classification of fibromyalgia at this stage.