Purpose: The purpose of this study was to investigate dementia related characteristics of demented elderly and determine the factors affecting care burden of caregiver. Method: The subjects of this study were 139 caregiver of demented elderly who enrolled in elderly senior centers in Seoul, Kyunggi and Inchon Province, Korea. Data were analyzed with descriptive statistics’ t-test, ANOVA, Pearson correlation, Multiple regression using SPSS/WIN 11.0 program. Results: Mean scores of dementia related characteristics of elderly were as follows: ADL & IADL 3.86, change of character 3.20, cognitive function 3.14, problem behavior 2.49, dementia level 2.47(moderate level). Mean score of care burden of caregiver was 2.93. The degree of care burden was significantly dependent on educational level, relationship to the elderly, occupation and health status of caregiver. The main effective variables on care burden of social activity limits were cognitive function, educational level of caregiver, those on care burden of negative change among demented elderly and caregiver were problem behavior, cognitive function and health status of caregiver. Psychological burden was predicted by health status of caregiver, problem behavior, cognitive function. Physical burden was predicted by ADL & IADL, health status of caregiver and problem behavior. Economical burden was predicted by monthly income of family, problem behavior, health status of caregiver. Conclusion: Therefore, based on dementia related characteristics of demented elderly and condition of caregiver, it is necessary to develop various educational and counsel program to decrease burden of caregiver.