The study of 15 cases of progressive cerebellar atrophies, and especially of the olivopontocerebellar atrophy, that was investigated both clinically and anatomically, has attempted to evidence particularities and correlations existing between these two types of atrophy. Olivopontocerebellar atrophy appears to be an abiotrophy of the cerebellum, considered to be spontaneous, sporadic, and sometimes with a hereditary familial background. It is a systemic disease, predominantly of the neocerebellum and involving the cerebellopedal system. It is at the opposite end of Holmes-type atrophies, and of the cerebello-olivary atrophies of the young (I. T. Niculescu, Th. Hornet, 1936) which mainly involve the paleocerebellum. The disease has a polymorphous symptomatology, it has a slow, progressive evolution with mostly cerebellar signs, with extrapyramidal phenomena and psychical disturbances due to lesions of the telencephalic pathways, and sometimes of the spinal, cerebellar and bulbar proprioceptive afferences, with spinal and bulbar involvement (Cezar Ionel, 1949, 1972).