Ganser syndrome (GS) is one of afew eponyms that have survived in psychiatry until the present day. GS is a little-known and rare disorder. It is most often described as a response to a stressor (e.g. incarceration), that is why it is an important issue in forensic psychiatry. Organic causes are taken into consideration. The basic symptoms of the syndrome are: approximate answers, visual and auditory hallucinations, clouding of consciousness and conversion symptoms. Additionally, patients may perform activities in an awry manner and suffer from insensitivity to painful stimuli.GS is usually acute and subsides spontaneously. Usually patients do not remember they had an episode of the disease. Diagnostic criteria of GS are imprecise and its classification has been changed over the years. GS was not listed in the DSM-5 classification, although in the DSM-IV it was classified as a dissociative disorder. Currently some authors tend to classify it rather as a factitious disorder. WHO (ICD-10 and ICD-11) classifies GS as a dissociative and conversion disorder, which seems to be appropriate in the light of current knowledge. The presented case report describes apatient with a nearly identical pattern of full-blown GS, which occurred twice. The symptoms appeared shortly after the patient was incarcerated. The course of the disorder was chronic and recurrent. The patient was insensitive to pain stimuli. Somatic causes were excluded in the diagnostic process.