This chapter analyzes the neuropsychological deficits in inherited cerebellar diseases and compares their symptomatology with animal models in which the exact anatomical localization of degeneration is known and limited to the cerebellum. Both animal and human data suggest that cerebellar cortical atrophy affects functions of the frontal lobe system. Olivopontocerebellar atrophy is genetically and clinically in homogeneous. The dementia syndrome that occurs in a proportion of patients does not seem to be linked with cerebellar dysfunction. Patients suffering from Friedreich's disease have been described as exhibiting cognitive slowing and deficits in spatial tasks. Because other structures are more prominently involved than the cerebellum in this disease, other pathoanatomical correlates may explain the symptomatology.