Delusional misidentifications include the Capgras delusion, Fregoli delusion, the delusion of subjective doubles and other less frequent symptoms. A common denominator of these unspecific psychopathological symptoms is the patients' denial of their identity or the convinction that their identity or the identity of relatives has been altered. These delusional symptoms occur in the context of somatic and mental diseases, most frequently in schizophrenia and dementia. According to neuropsychological and neuroanatomical studies delusional misidentifications are facilitated by lesions of the temporo-limbic system leading to an impairment in the affective recognition and reality control. Patients suffering from delusional misidentifications have a higher risk of aggressive behaviour which emphasises their clinical relevance.