108 female and 69 male Iranian university students, during the stressful period of final exams, responded to the following scales: Integrative Self-Knowledge (Ghorbani, 1385), Mindfulness Attention Awareness (Brown & Ryan, 2003), Private Self-Consciousness (Fenigstein et al., 1975), Defense Styles (Andrews, et al.,1993), Perceived Stress (Cohen et al., 1983), Subjective Vitality (Ryan & Fedrick, 1997), Symptom and Illness (Watson & Pennebaker, 1989), and Symptom Checklist (Barton, 1995). The main hypothesis was that self-knowledge processes would be negatively correlated with illness and unhealthy defensive styles, where integrative self-knowledge plays the key role. Data showed that, among different self-knowledge pricesses, only integrative self-knowledge predicted illness, symptoms, vitality, and healthy defensive styles. In addition, integrative self-knowledge and internal state awareness predicted mature defensive styles and perceived stress. Minfulness was negatively related to the immature defensive styles.