BACKGROUND: Interest in smartphone health apps has been increasing recently. However, we have little understanding of the cognitive and motivational factors that influence the extent of health-app use. OBJECTIVE: This study aimed to examine the effects of four cognitive factors-health consciousness, health information orientation, eHealth literacy, and health-app use efficacy-on the extent of health-app use. It also explored the influence of two different use patterns-information and information-behavior use of health apps-with regard to the relationships among the main study variables. METHODS: We collected and analyzed 765 surveys in South Korea. According to the results, there was a negligible gender difference: males (50.6%, 387/765) and females (49.4%, 378/765). All participants were adults whose ages ranged from 19 to 59. In order to test the proposed hypotheses, we used a path analysis as a specific form of structural equation modeling. RESULTS: Through a path analysis, we discovered that individuals' health consciousness had a direct effect on their use of health apps. However, unlike the initial expectations, the effects of health information orientation and eHealth literacy on health-app use were mediated by health-app use efficacy. CONCLUSIONS: The results from the path analysis addressed a significant direct effect of health consciousness as well as strong mediating effects of health-app use efficacy. These findings contribute to widening our comprehension of the new, digital dimensions of health management, particularly those revolving around mobile technology.