The systolic hypertension in Europe (Syst-Eur) trial has been the only trial that has suggested a protective effect of antihypertensive treatment on incidence of dementia. It is unclear whether this protective effect has been caused by the blood pressure lowering effect of the calcium antagonist nitrendipine or by the calcium channel inhibition. From the Leiden 85-plus study, a population-based cohort study of 599 subjects aged 85 years, we selected 204 subjects who used at least one antihypertensive at baseline. Associations between use of antihypertensives at baseline and change in cognitive functioning over time were assessed with linear mixed models. After adjusting for gender, education, and use of other antihypertensives, only use of calcium antagonists was associated with a significant decelerated annual cognitive decline during follow-up (0.40 MMSE-points per year, p=0.001). Use of other antihypertensives was not associated with a decelerated annual cognitive decline (all p values >0.3). Our data support the interpretation that the reported prevention of dementia by calcium antagonists is exerted through its calcium channel inhibition rather than its blood pressure lowering properties.