The project Epidemiology Research on Dementia in Antwerp (ERDA) estimated the prevalence of dementia in a random, population-based sample, stratified for age and sex. The sample of 1,736 elderly was screened at home with the Mini-Mental State Examination. All elderly under the cutoff of 23–24/30 got a diagnostic examination with the Cambridge Mental Disorders of the Elderly Examination and the DSM-IIIR criteria. The prevalence of dementia in the population above 65 years was estimated at 9%. The following age-specific prevalences of dementia (included mild dementia) were found in the age-groups 65–69, 70–74, 75–79, 80–84, 85+: 0.6, 5.1, 7.6, 16.2 and 33.6%. The prevalence of at least moderate dementia was 0.3, 3.9, 4.0, 11.2 and 25.0%, respectively. The prevalence of dementia, vascular dementia and dementia of the Alzheimer type was markedly higher in women th