Development of a capacity-building program for older adults in health management and promotion is necessary for readiness for the complete-aged society in Thailand. Little is known about programs that reinforce older adults' capacities in health management and promotion in urban communities. This research and development design aimed to develop and determine the effects of a capacity-building program on health management and promotion for older adults in urban communities. A program was held in two sections totaling 90 hours, including coursework and practical sections. This program covered health education, chronic condition management, and health promotion for older adults. The program was evaluated for appropriateness and feasibility by five experts. Forty-four older adults met the criteria and were selected by simple random sampling from nine communities. Data were collected using questionnaires at baseline, post-intervention, and a 1-month follow-up after the end of the intervention. The instruments used for data collection included a demographic questionnaire, a self-assessment on the capacity of older adults, and a self-assessment competency questionnaire on health management and promotion. Descriptive statistics and paired sample t-test were used for the data analysis. After the intervention, the findings showed that the mean score of the capacity of older adults was significantly higher than before receiving the intervention (38.61 ± 4.03, p <.001). When comparing each dimension, the results found the mean scores for knowledge, attitude, and capacity for health management and promotion of older adults to be 11.77 ± 1.79, p <.001, 4.09 ± .39, p <.001, 3.72 ± .057, p <.001, respectively. The one-month follow-up revealed that most older adults had a moderate (53.3%) and high (46.5%) level of health management and promotion competency. This study indicates that the capacity-building program for older adults is effective and needs to be implemented in urban communities.