The last comparison of prevalence figures of dementia across European studies was 10 years ago. Using studies conducted in the 1990s, the authors compare the age- and sex-specific prevalence of dementia, AD, and vascular dementia (VaD) across European population-based studies of persons 65 years and older. Data from these studies were also pooled to obtain stable estimates of age- and sex-specific prevalence. A total of 2346 cases of mild to severe dementia were identified in 11 cohorts. Age-standardized prevalence was 6.4% for dementia (all causes), 4.4% for AD, and 1.6% for VaD. The prevalence of dementia increased continuously with age and was 0.8% in the group age 65 to 69 years and 28.5% at age 90 years and older. The corresponding figures for AD (53.7% of cases) were 0.6% and 22.2%, and for VaD (15.8% of cases), 0.3% and 5.2%. Variation of AD prevalence across studies was greatest for men. In the VaD subtype, a large variation across studies was observed, as well as a difference in prevalence between men and women that was age dependent. Dementia is more prevalent in women, and AD is the main contributor to the steep increase of prevalence with age.