Purpose: This study was aimed at finding factors influencing cognitive impairment which is one of the typical symptoms among the demented elderly. Methods: The number of subjects was 417 elderly residents aged over 65 yr in a community. A cognitive function and a depression level were measured using the Korean Version of Mini-Mental State Examination (MMSE-K) and the Korean Form of Geriatric Depression Scale (KGDS). Alcohol abuse was measured using the CAGE instrument. Chi-square test and Logistic regression analysis were conducted to identify factors affecting cognitive impairment. Results: The prevalence rates of cognitive impairment of the sample was 43.5%. Sex, age, educational level, perceived health and alcohol abuse were strong factors influencing cognitive impairment. However, the effects of smoking, living alone, depression, family history in dementia and stroke were not strong. Conclusion: Risk for cognitive impairment were increased by being female and older than 70 yr, having low education, perceiving health as poor, and drinking alcohol abusively. Therefore, a reinforcement system, continuous research and the development of proper programs should be preformed in order to prevent cognitive impairment.