Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet #Preprint #PeerReviewMe: Warning: This is a unreviewed preprint. Readers are warned that the document has not been peer-reviewed by expert/patient reviewers or an academic editor, may contain misleading claims, and is likely to undergo changes before final publication, if accepted, or may have been rejected/withdrawn. Readers with interest and expertise are encouraged to sign up as peer-reviewer, if the paper is within an open peer-review period. Please cite this preprint only for review purposes or for grant applications and CVs (if you are the author). Background: In Korea, most self-management of chronic diseases are trained through face-to-face education primarily at healthcare setting. Therefore, older Koreans living in the community continue to seek other training opportunities to learn chronic disease management using new training methods, such as mobile health (mHealth), which are valuable in community settings. Objective: This feasibility study (1) developed an mHealth training protocol to empower older adults to manage their chronic diseases at home, (2) examined the feasibility of the mHealth training protocol using mobile tablets and applications (apps), and (3) discussed contextual and methodological challenges when applying an mHealth training protocol for older Koreans with chronic diseases. Methods: The mHealth training protocol was developed based on the eHealth Enhanced Chronic Care Model and consisted of four phases. Phase 1 included mobile tablet training and standardized technology training with guidebooks, demonstrations, and guided practice. Phase 2 included standardized information for disease management retrieved from both governmental and professional healthcare organizations. Phase 3 included training to use the pre-selected high-quality mHealth apps to consider types of individuals’ chronic disease. Phase 4 included encouragement to practice self-selected mHealth apps based on their individual needs. Quantitatively descriptive and qualitative content analyses of user evaluations were completed to assess feasibility and user acceptance. Results: Among the 27 older adults, 25 completed mHealth training for 4 weeks. The attrition rate was 7.4% (2/27), due to time conflicts, emotional distress, and/or family discouragement. The men required little or no training for Phase 1, while the women seemed to depend more on the mHealth trainers for Phase 3 than men. At least 4 weeks of weekly meetings were required to complete the training with mHealth training protocol. Gender, education level, and previous experience using smartphones were associated with learning speed, confidence, and competence. Conclusions: A tailored and personalized approach is required to develop mHealth training protocols for older adults. Self-management of chronic diseases via mHealth training requires careful consideration regarding the complex nature of human behavior, emotional response, and family influence; therefore, integrating a theoretical-clinical-technical approach is necessary for the development and implementation of mHealth training targeting older adults with chronic diseases in a community setting.