Background: The purpose of this study is to determine how the cognitive state of the elderly influences the activities of daily living(ADL) in order to increase their achievement capacity and their ability to exercise this capacity in daily life. The MMSE-K(Mini-Mental State Examination-Korean) was used to evaluate the daily activities and cognitive state of a group of subjects more than 65 years of age. The goal was to understand (1) How their achievement level in their daily activities changes according to the increase and decrease of their cognition points by analyzing and comparing their achievement points in the mental state examination, and (2) What variables influence that daily achievement level. Methods: The survey was conducted by a group of students from AnSan College who were trained for this method of data collection. The group surveyed 224 senior citizens older than 65 to determine their ADL performance. The subjects were selected from Silver Care Centers in the Gyounggi Province area including centers in Suwon, Anyang, Kwachun, and Sanbon City. The subjects were given enough information to fully understand the purpose of the study and the method by which it would be conducted. The survey method was a direct interview: which involved an interviewer reading the questionnaire to the subject and recording the answer. Result: The following results were calculated using SPSS WIN ver. 13.0: In the lower score of the MMSE-K regarding ADL performance (K-MBI) for activities such as individual hygiene, bathing activity, food activity, toilet management, going up stairs, getting dressed ad undressed, controlling stools and urination, walking, and chair/bed movement, most of the subjects responded that they could not perform these activities by themselves (p<.01). In the higher scores for the same activities, most response that they could perform the tasks by themselves (p<.01). In the results of the multiple regression analysis, there influence of the variables for ADL performance (K-MBI) and MMSE-K score was higher for females than males. Conclusion: This study evaluated the cognitive state of the elderly using the MMSE-K, which is the most convenient method, and examined how the cognitive state influences the achievement capacity of the daily lives with other variables. In conclusion, the higher the score on the MMSE-K, the more independent the elders are in the activities of daily living, especially among women more than men.