This research was to assess the health knowledge level and health promoting behavior of the elderly, and to determine the causal relations between them. The questionnaires 86 items were administered to a total of 915 elderly participants who consisted of 798 community-dwellers of both rural and urban areas and 117 nursing home residents. The level of health knowledge was much higher in the urban community-dwellers than others, whereas the level of health-promoting behavior was much higher in the nursing home residents than the community-dwellers. In addition, the economic status was the most powerful variable to explain the health knowledge, while the interest in health was the most powerful variable to explain the health-promoting behavior. The causal relations between the health-promoting behavior and the health knowledge as well as the other socio-demographic variables were sought with a path model. The findings were discussed in the context of establishing public health policies and developing health education programs to promote the health of the elderly.