An epidemiological survey of age-related dementia among community residents of an urban of Beijing was conducted in 1986. Initial screening of 1331 subjects aged 60 and above was made using the Mini-Mental State Examination (MMSE) with a cutoff point of 17. All suspected cases of dementia and 5.5% of all others were then given a full clinical examination, with subjects being diagnosed and classified according to DSM-III criteria. The MMSE was found to have satisfactory sensitivity, although scores were significantly correlated with education. Prevalence rates of moderate and severe dementia were 1.28% for those aged 60 and above and 1.82% for those aged 65 and above. Rates for multi-infarct dementia were higher than those for primary degenerative dementia; females had higher rates than males and rates increased sharply with age. All the dementia cases were cared for in their own homes, by relatives. There is a need for increased knowledge and services for elderly people in the community.