Thiamine or vitamin B(1), an essential nutrient absorbed from the diet, is involved in vital brain metabolic and cellular functions, including carbohydrate metabolism and neurotransmitter production. Diencephalic regions and, in particular, the cerebellum demonstrate lesions in cases of prolonged thiamine deficiency, such as that observed in alcohol-dependent individuals or in patients with cancer or AIDS. The purpose of this review is to demonstrate recent evidence of cerebellar dysfunction resulting from thiamine deficiency and to assemble theories as to why the cerebellum may be sensitive to this type of insult. A brief outline on cerebellar structure and function, as well as a short discussion on thiamine and thiamine deficiency are provided before detailing the conditions and mechanisms underlying thiamine deficiency-induced cerebellar dysfunction. Although much is known regarding cell loss from a lack of thiamine, further work is still required to identify the sequelae of events leading to the susceptibility of the cerebellum to injury stemming from a thiamine deficient diet or impaired thiamine utilization.