The challenges inherent in the higher education environment and emerging adulthood make undergraduates a suitable target population for the study of resilience factors and health outcomes. However, so far, only a limited number of studies have examined the relationship between psychological resilience and physical health outcomes in healthy populations such as undergraduates. Moreover, although substantial evidence has demonstrated an association between higher levels of resilience and better health, the mechanisms translating resilience into better health are still elusive. The PI and his associates addressed these issues in a recent study with Chinese undergraduates, using salivary cortisol as the health outcome measure (Lai, Leung, Lee, Lam & Berning, in press). Despite the limitation of a small sample size, the finding of an association between higher resilience and a greater increase in morning cortisol and a faster drop in cortisol over the course of the day is inspiring, as this diurnal cortisol rhythm has been observed in better-adjusted or healthier individuals in prior studies. This “dynamic” cortisol rhythm may explain the well-documented association between resilience and better health. These findings and their implications provide a sound justification for extending the findings reported by Lai et al. (in press) using a larger sample and more vigorous analytic strategies. The potential impact of studying resilience and cortisol in a Chinese context is more apparent in light of recent findings showing for the first time the moderating effect of ethnicity and culture on the relationship between diurnal cortisol rhythms and health outcomes. This calls into question the continuing use in Asia of norms of diurnal cortisol rhythms established in studies with Western samples. In response to the aforementioned issues, the proposed study will examine the relationship between resilience, diurnal cortisol rhythms, and health outcomes in Chinese undergraduates from Hong Kong and Taiwan using a more vigorous method to model the diurnal cortisol rhythm. We expect that the proposed study will have the following long-term impacts. 1. Stimulating research on resilience and cortisol by arriving at a more precise characterization of the diurnal cortisol rhythm in better-adjusted individuals. 2. Highlighting the mechanisms translating resilience into better health or reduced morbidity. 3. Providing a reliable biological criterion for evaluating the effectiveness of interventions designed to promote resilience or well-being in Chinese undergraduates. 4. Serving as the first step in establishing Chinese norms for diurnal cortisol rhythms in the long run using a standardized protocol.