The objective of this study was to compare the mortality rate of demented and nondemented subjects in a single cohort. We followed up a cohort of subjects comprising all 1259 inhabitants of Leiden aged 85 years and over, evaluated earlier for the presence of dementia, and including institutionalized subjects. The main outcome measure was the mortality rate ratio of the demented and nondemented groups adjusted for age and sex. The mortality rate ratio of the demented vs the nondemented group was 1.9 (95% confidence interval: 1.7-2.2). No difference in mortality rate was found between those with mild vs moderate to severe dementia. The mortality rate in dementia patients is higher than in nondemented subjects.