Fibromyalgia syndrome (FMS) affects 0.4-8% of the general population predominantly in the female population with a F:M ratio of 3-9:1. It is characterised by persistent widespread pain and other associated clinical conditions such as chronic fatigue, irritable bowel syndrome (IBS), temporomandibular joint dysfunction (TMJD), sleep disorders and cognitive impairment. FMS diagnosis at present is purely clinical because no medical or laboratory examinations are able to identify it with certainty. FMS is not fully recognised worldwide, and patients often do not receive the treatment and disability benefits planned for other chronic diseases even though it gives rise to a very significant social burden due to direct and indirect healthcare costs and the loss of productivity and work. This article describes the medico-legal situation of FMS patients around the world, particularly issues related to the recognition of the disease by health institutions and the provision of disability benefits. We also discuss the current means of assessing disabilities in the medico-legal context, and their possible future improvements.