BACKGROUND: The prevalence of cognitive impairment in the elderly has been increasing in recent years with the growing of the aged population. Clinical assessment of cognitive function and mood is very important because cognitive impairment and depression commonly coexist in the elderly. The elderly interacts with the other family members, so cognitive impairment of the elderly influence family function. The objectives of this study were to delineate the factors correlated with cognitive function and to explore the relationship of depression and family function with cognitive function. METHODS: This study was done during 20 day period from July to August, 1996. The subjects were home residents aged 60 years or more living in a subcounty of Kyungpook Province, Korea. The final analysis included 195 subjects(male 95, female 100). The questionnaire included sociodemographic data, MMSE-K(Korean version of Mini Mental State Examination) for evaluation of cognitive function, BDI for evaluation of depression and family APGAR score for evaluation of family function. The results were analyzed by descriptive, comparative and correlative analysis. RESULTS: Mean MMSE-K score was 25.3+/-4.3 with female subjects(23.9+/-4.8) having significantly higher cognitive impairment when compaired to male subjects(26.6+/-3.2)(P<0.001). MMSE-K score was associated with gender, age, year of education(P<0.001), BDI and APGAR score(P<0.05). Religion, smoking and alcohol use were not associated with MMSE-K score. The prevalence of dementia by MMSE-K was 9.7% in definite dementia (MMSE-K<_19) and 23.1% with questionable dementia(20<_MMSE-K<_23). In male, the prevalence was 1.1% and 20.0% respectively. In female, the prevalence was 18.0% and 26% respectively, indicating difference between male and female subjects(P<0.001). CONCLUSIONS: In the elderly, female gender, older age and lower educational level were associated with cognitive function impairment. There was a positive correlation between cognitive function and family function. The group with impaired cognitive function had more depression than the normal group.