The concept of cerebellar atrophy was first introduced by Pierre Marie in 1893 in his description of hereditary cerebellar ataxia. Subsequent criticism of this notion was refuted by the report of new clinicopathological entities which are compatible with it. The contributions of the Clinic for Diseases of the Nervous System are discussed in this paper. Etiological classification is difficult, in spite of progress made in the genetic, epidemiologic, and biochemical approaches to cerebellar atrophies. Pathologic findings appear to supply the most secure basis for presentation of these affections. Predominantly cortical atrophies may be localized to the vermis. This is the case in the familial cerebello-olivary atrophy of Holmes (1907), in tardive cortical atrophy (Pierre Marie, Foix and Alajouanine, 1922), and in the cerebellar atrophy of alcoholics (Alajouanine, Castaigne, Contamin and Lebourges, 1959; Victor, Adams and Mancall, 1959), in which the lesions are similar. The frequent intrication of the various etiological factors: age, deficiencies, alcohol, heredity, suggests the role of a sometimes primary, sometimes latent genetic predisposition, revealed during various pathological conditions. Cortical cerebellar atrophy may be of the diffuse type, as in paraneoplastic cerebellar atrophy (Brouwer and Biemond, 1938), which is closely related to subacute polioencephalomyelitis in cancer patients (Dubas et al., 1982), and in congenital atrophy of the granular layer (Norman, 1940), which is more a dysgenesis than a true degenerative affection. Lesions affecting mainly the efferent or afferent cerebellar pathways include olivopontocerebellar atrophy (Dejerine and André Thomas, 1900) which should be included in the larger overall concept of multiple system atrophy (Oppenheimer, 1976), and dentorubric atrophy (Ramsay Hunt, 1921) which themselves should be integrated in the group of spinocerebellar atrophies. Finally, olivorubrocerebellar atrophy (Lejonne and Lhermitte, 1909) and crossed cerebellar atrophy, traditionally studied together with cerebellar atrophies, are only the result of a pre-existing lesion.