This research aimed to 1) study the health situation of the elderly, 2) develop online media in the form of a rhythmic activity application that promotes health of the elderly, and 3) study the satisfaction of using online media in the form of a rhythmic activity application that promotes health of the elderly. The sample group used in the research was 50 elderly members of the Makok Wittaya School for the Elderly, Ban Makok, Kham Riang Subdistrict, Kantharawichai District, Maha Sarakham Province, who were selected by purposive sampling. The research instruments were the health situation questionnaire of the elderly, online media in the form of an application, the quality and appropriateness assessment form of online media in the form of an application, and the satisfaction assessment form of the elderly. The statistics used in the research were the mean and standard deviation.
         The results of the research found that the health situation of the elderly in practicing their own health was at a moderate level overall ( =3.24, S.D.=0.84). The results of the development of online media in the form of an application were divided into 3 parts: the system access part, the main activities in the application, and the application data part. The results of the evaluation of the quality and appropriateness of rhythmic activities in the form of online media by experts Overall, it was at the highest level (=4.55, S.D.=0.50) and the results of the study of satisfaction with the use of rhythmic activities of online media in the form of an application that promotes the health of the elderly found that the elderly had overall satisfaction at a high level (=3.54, S.D.=0.61) and were satisfied with their overall health at a high level (=4.02, S.D.=0.66).