The authors report the prevalence of dementia in a community-dwelling Brazilian elderly population and correlate prevalence data with educational and socio-economic levels. The study was conducted in Catanduva, Brazil. A total of 1,656 randomyl selected subjects aged 65 yeas or more were submitted to a health questionnaire, the Mini-Mental State Examination (MMSE), anda the Pfeffer Functional Activities Questionnaire (PFAQ). According to the PFAQ and MMSE scores, selected subjects were submitted to clinical, neurologic, and cognitive evaluations. The subjects diagnosed with dementia underwent laboratry test and brain computed tomography (CT). Dementia was diagnosed in 118 subjects, corresponding to a prevalence of 7.1%. The main clinical diagnose were Alzheimer disease (AD; 55.1%), vascular dementia (9.3%), and AD with cerebrovascular disease (14.4%). The prevalence increased with age and was higher in women. There was an inverse association with education (3.5% among persons with 8 or more years of schooling to 12.2% among those who were illiterate). Multivariate analysis disclosed significant association between these three variables and dementia. The prevalence of dementia in this Brazilian population was 7.1% and AD was the most frequent diagnosis. Age, female gender, and low educational level werer significantly associated with a higher prevalence of dementia.