This study aimed to examine and identify the predictors of Yangsaeng (health management) among Korean middle-aged adults. A cross-sectional descriptive design was employed. Study participants consisted of 150 middle-aged adults in S and G cities, South Korea. Measures included the Yangsaeng scale, the perceived health state scale, the self-efficacy scale, the Beck Depression Inventory, and the family support scale. The analyses showed that the prediction model for Yangsaeng (health management) among Korean middle-aged adults was significant. The value of the adjusted R was 0.635, which corresponded to the explanatory power of 63.5%. The predictor with the most influence on Yangsaeng (health management) among Korean middle-aged adults was family support, followed by perceived health state, leisure activity, self-efficacy, and religion, respectively. This study provided preliminary evidence that family support is a major and primary predictor of Yangsaeng (health management) among Korean middle-aged adults. Concrete interventions and strategies to improve the Yangsaeng (health management) of Korean middle-aged adults were necessary.