This study was done to identify family burden, resilience, spiritual well-being and quality of life of primary caregivers of people with mental illness. Methods: Participants were 160 primary caregivers of people with mental illness being treated at one of three mental health clinics in Busan. Data were analyzed using descriptive statistics, t-test, ANOVA, Scheffe test, Pearson`s correlation coefficients and stepwise multiple regression. Results: Quality of life was positively correlated with resilience (r=.55, p=.006), spiritual well-being (r=.41, p<.001), and negatively correlated with family burden (r=-.28, p<.001). Factors influencing quality of life were resilience (β=.36), family monthly income (β=.24), support from others (β=.20) and education (β=.18). The explanatory power of these factors for quality of life of primary caregivers of people with mental illness was 45%. Conclusion: Findings indicate that resilience is the most important factor affecting quality of life of primary caregivers of people with mental illness. Therefore, the development of nursing interventions to improve resilience and enhance the quality of life of primary caregivers is necessary.