A survey was made of 2,792 subjects aged 65 and older living in the community of Gironde (South-Western France). The predictive value of the Mini-Mental state examination (MMS) as a screening instrument for the detection of cognitive impairment was tested against DSM-III criteria for dementing syndromes. Of the 2,792 subjects who consented to participate in the study, 101 met the DSM-III criteria for dementia, giving a 3.62% prevalence rate. With an MMS threshold of 24, the sensitivity was 100%, the specificity was 78%, and the positive predictive value was equal to 15%. Using the same MMS threshold, 572 subjects (85%) were false-positive for the diagnosis of dementia. A multiple logistic regression analysis revealed that age, sex, depressive symptomatology and educational level were independently correlated with false-positive cases of the MMS. Several issues are raised for using the MMS as the only screening instrument for cognitive impairment in elderly community residents.