The purpose of this study was to investigate the factors influencing quality of life of chronic mental illness. The subjects of this study were 190 patients with chronic mental illness diagnosed by physician, over the age of 20, living in Seoul, Korea, during the period from May, 2000 to December, 2000. The instruments for this study were the quality of life scale by RoYooJa(1979), the self-esteem scale by Rogenberg(1965), social support scale by ParkJiWon(1985), coping behavior scale by Shirley Zeitlin(1978)m self efficacy scale by Sherer et. al(1982), and Rand mental health inventory(1979). The data were analyzed using descriptive statistics, Pearson correlation coefficients, and stepwise multiple regression. The results of this study are as follows: 1. The quality of life showed significant positive correlation with self-esteem(r=0.75, p=0.00), self-efficacy(r=0.53, p=0.00), social support(r=0.49, p=0.00), self-oriented coping(r=0.36, p=0.00), and environment-oriented coping (r=0.34, p=0.00). 2. The quality of life showed significant negative correlation with anxiety(r=-0.73, p=0.00), depression(r=-0.58, p=0.000), and psychological distress(r=-0.35, p=0.000). 2. Stepwise multiple regression analysis revealed that the most powerful predictor of quality of life was self esteem(36%). A combination of self esteem, social support, self efficacy, psychological distress, self oriented coping, and environment oriented coping behavior account for 55% of the variance in quality of life in chronic mental illness. From the results of this study, it is suggested to develop and apply comprehensive intervention program for improve quality of life in chronic mental illness.