People experiencing somatic symptoms for which there is no medical explanation constitute up to approx. 20% of the population. The lack of data concerning etiology of ailments such as chronic fatigue or headaches, back pain and stomach-ache, impede diagnostics and treatment. There is no clear terminology referring to the described ailments. Despite many ambiguities, numerous clinical trials bring about increasingly extensive data concerning treatment which results in implementation of standards of conduct in diagnostics and treatment. Many of them indicate high efficiency of cognitive behavioural therapy in selected sets of symptoms. It is a type of psychotherapy in which the impact of cognitive processes and the manner of thinking on emotional functioning is given significant meaning. This therapy applies techniques of changing behaviours and maladaptive beliefs, aiming at better management of stress and difficult emotions. This elaboration arranges data concerning research on cognitive behavioural therapy in treating patients with the MUS syndrome, i.e. medically unexplained symptoms. Reviews of research and recommendations of organizations involved in improvement of health care, such as NICE, were used. Examples of medically unexplained symptoms which have been most extensively studied were discussed such as chronic fatigue syndrome, irritable bowel syndrome and fibromyalgia. Also, the manner of understanding and therapy methods of the listed diseases were presented. Final conclusions consider implementation of the collected data in clinical practice. They highlight the essence of cooperation between health care specialists for complex treatment of patients with medically unexplained symptoms.