The population-based Helsinki Aging Study was comprised of three age groups: 75-, 80- and 85-year-olds. A random sample of 511 subjects completed the Mini Mental State Examination (MMSE) and were assessed on the Clinical Dementia Rating-scale (CDR). According to the CDR results 446 subjects were screened as non-demented. Of these subjects 30% scored below or at 24 MMSE points. Age, education and social group had a significant effect on the MMSE scores, even after excluding the demented cases. Together they explained 10% of the total variance within the MMSE. Social group correlated with education. The MMSE scores were corrected according to age and education. Adjustment of the originally used cutpoint of 24 resulted in cutpoints of 25 and 26 among the 75-year-olds, in the low and high education groups respectively; 23 and 26 in the 80-year-olds; 22 and 23 in the 85-year-olds.