Proteasomes (including constitutive proteasome, immunoproteasome, and their regulatory complexes) are multicatalytic complexes crucial for cell and body homeostasis and survival, being responsible for a consistent part of protein degradation. In the central nervous system (CNS), the activity of proteasomes affects a variety of crucial brain activities. While proteasome alteration (content and activity) during aging has been studied in several tissues and cellular models, few data are available regarding human CNS, and the identification of an appropriate and reliable model for the role of proteasome in human brain aging is still lacking. In this review, the available data on proteasome and brain aging in rodents, as well as the few data on non human primates, are critically revised. On the whole, the data regarding changes of proteasome activity and content with age are far from being clear, not only due to the heterogeneity of the models (differences between species, among strains of the same species) but also due to the brain areas considered. We paid particular attention to recent data obtained in human brain of non-demented donors and subjects affected by Alzheimer Disease (AD) demented subjects, as well as to new data on non human primate brain. The study of the possible role of proteasomes in brain aging, and the identification of reliable animal models, is pivotal for the development of possible ad hoc therapeutic interventions capable of retarding/counteracting brain aging and age-related brain pathologies. The therapeutic capability and limits of Vitamin E, the possible set up of proteasome modifiers (activators) as well as the effects on proteasomes of other drugs used for AD therapy are discussed within a scenario which deserves more attention and further investigations.