Fibromyalgia syndrome (FMS) is one of the most common chronic pain syndromes. In a representative survey, 2.1% of the German population was affected in 2013, whereby the diagnosis can only be made on the basis of subjective complaints. This article should provide concrete information on the disease concept, diagnosis, therapy, rehabilitation and socialmedical assessment at the FMS. The basis for this is the second update of the S3 guideline to the FMS adopted in 2017.