OBJECTIVE: The imagination of being transformed into an animal or being an animal is called lycanthropy. The phenomenon is presented and psychodynamical aspects are discussed. METHOD: A literature review forms the base of this discussion of a psychopathological phenomenon. RESULTS: The lycanthropic symptomatology represents a spectrum of continuity of developmental and culture-dependent normal behaviour via partial forms to the complete picture of lycanthropy. It is observed in different mental disorders. CONCLUSION: Lycanthropy is interpreted by the authors as a delusion in the sense of the self-identity disorder defined by Scharfetter. It is mainly found in affective and schizophrenic disorders but can be a symptom of other psychiatric disorders as well. Psychodynamically this kind of delusion can be interpreted as an attempt to project suppressed affects, especially with aggressive or sexual content, into the figure of an animal. Psychotherapy and/or neuroleptic medication can be effective.