The purpose of this study was to investigate the factors influencing social adaptation of chronic mental illness. The subjects of this study were 190 patients, over the age of 20 with chronic mental illness diagnosed by a physician, and living in Seoul, Korea during May, 2000 to December 2000. The instruments for this study were the social adaptation scale by Wallace (1979), the self-esteem scale by Rogenberg (1965), social support scale by ParkJiWon (1985), coping behavior scale by Shirley Zeitlin (1978), 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 level of social adaptation showed moderate (M=3.43). 2. The social adaptation showed significant positive correlation with self-esteem (r=0.39, p=0.00), self-efficacy (r=0.31, p=0.00), social support (r=0.47, p=0.00), self-productive coping (r=0.14, p=0.05), self-flexible coping (r=0.22, p=0.00), environment-active coping (r=0.21, p=0.00), and environment-flexible coping (r=0.14, p=0.04). The social adaptation showed significant negative correlation with anxiety (r=-0.16, p=0.02), and emotional problems (r=-0.18, p=-0.00). 3. The stepwise multiple regression analysis revealed that the most powerful predictor of social adaptation was social support (21%). A combination of social support, depression, behavioral controllability, self-efficacy, and environmental coping behavior accounted for 39% of the variance in social adaptation in chronic mental illness. From the results of this study, it is suggested to develop and apply a social adaptation training program for chronic mental illness.