Objective: To determine the risk of dementia after first-ever ischemic stroke. Background: A temporal relationship between the occurrence of stroke and development of dementia is an important clue for a vascular etiology of dementia. It is however still unclear at what rate dementia develops following stroke. Methods: In a prospective study, we followed 158 consecutive patients who were hospitalized for first-ever ischemic stroke in 1988–1989, but were not demented at discharge (DSM-III-R criteria). Survival analysis was performed for a follow-up period of up to 3 years to determine the rate of dementia. Results: The cumulative risk of dementia in these patients was 29% within 1 year, and 34% within 3 years. Conclusion: Dementia after first-ever ischemic stroke is common, appearing mostly within the 1st year.