Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain and generalized hypersensitivity to painful stimuli in the absence of external stimuli. A substantial number of patients with this condition also suffer from sleep disturbance, chronic fatigue syndrome, anxiety, and depression. The pathophysiology is not fully established. Central sensitization, abnormalities in the descending inhibitory pain pathways and psychological abnormalities have been proposed as etiological mechanisms. Diagnosis is based on the clinical criteria established by the American College of Rheumatology, physical examination, and the exclusion of other causes of the symptoms. Fibromyalgia syndrome (FMS) is a heterogeneous condition comprising a range of symptoms and features, and the therapeutic management if it is to be effective must take all of these factors into account. A full understanding of fibromyalgia requires a comprehensive assessment of pain, function and the psychosocial context.