The purpose of this study was to identify file-up stress, family hardiness and mental health status to examine factors influencing file-up stress in family caregivers caring for elderly dementia. Data were collected by questionnaires from 109 family caregivers for elderly dementia at public health center. Data were analyzed using descriptive statistics, Spearman correlation coefficients, and stepwise multiple regression. There was significant and negative correlation between file-up stress and family hardiness, and between family hardiness and mental health status; significant and positive correlation was found between file-up stress and mental health status. Anxiety was predictor of file-up stress. File-up stress, family hardiness, mental status in family caregivers caring for elderly dementia patient, and significant correlation between their relationships. Therefore, this study suggests that in developing interventions to manage for file-up stress, family hardiness and mental health status should be considered in family caregivers caring for dementia patients.