Chronic wasting disease (CWD) of cervidae, only known in three North American species of cervids, is one the oldest known of the prion diseases or transmissible spongiform encephalopathies (TSEs), and the only one naturally present in wild populations. The interest linked toCWDis quite new, linked to the European mad cow disease crisis. This review puts together the facts associated with the disease, trying to put forward its specificities and looking for possible developments. Even if known since quite a long time this TSE is still one of the least understood. It does represent a different disease. Some of the difficulties facing its study are linked to the fact that it concerns free-ranging wild species. Epidemiological and sanitary consequences are presented.