A now 58-year-old female patient, carrier of the point-mutation in the beta-amyloid gene on chromosome 21 which causes hereditary cerebral hemorrhage with amyloidosis - Dutch type, developed progressive dementia after the age of 55 years. She never suffered from a cerebral hemorrhage. Dementia has been described as a feature of hereditary amyloid angiopathy before, but only in patients who also suffer from strokes. The clinical manifestation of the patient described here underlines the relation between the Dutch type of hereditary amyloid angiopathy and (familial) Alzheimer's disease.