Fabry's disease, a rare X-linked disorder of glycosphingolipid metabolism, can present as an insidious dementia in middle or later life. This genetic disorder produces a deficiency of alpha-galactosidase A which results in the deposition of glycosphingolipids in blood vessel walls in the brain as well as in the kidney, heart, peripheral nerves, and other organs. Among the cerebrovascular manifestations of this disorder is a vascular dementia from involvement of multiple small penetrating blood vessels. Fabry's disease is a consideration in the workup of an otherwise unexplained vascular dementia, particularly in males less than 65 years of age.