Generalized tendomyopathy (GTM), or fibromyalgia, is a disorder characterized by diffuse pain in the musculoskeletal apparatus which usually begins at a single site, e.g., as low-back pain or cervical syndrome, and develops into generalized pain over months or years. It is accompanied by increased tenderness at characteristic tender points, although the pain threshold on the whole is reduced. In addition to the main symptoms (pain in the musculoskeletal system, tenderness at the tender points), autonomic and functional symptoms are almost invariably present and are often accompanied by pathological psychological findings such as neuroses and depression. To date, no reliable laboratory parameters or pathognomonic histological findings have been identified. The disorder affects primarily women, beginning around the age of 35 and reaching its peak during or after the menopause. It also affects young people and those over age 60, although it is much less common in these cases. Secondary forms are observed particularly in rheumatoid arthritis. The differential diagnosis must first distinguish primary GTM from the secondary forms. There must also be further differentiation between internal and psychiatric disorders and primary GTM. This can be achieved in many cases by careful clinical diagnosis, although a more complete examination is sometimes required.