Purpose: The purpose of this study was to examine the relationships among self-care, self-care agency, self-efficacy, and quality of life in type II diabetic patients registered at a public health center. Method: The study subjects were 128 type II diabetic patients who were living in G city. The data were collected from March 2001 to February 2002. The instruments used for this study were the self-care scale developed by Jeung(1997) and designed by Park (1984) based on the original scale, the self-care agency scale developed by So (1992), the self-efficacy scale developed by a Jeung (1997) and designed by Paek (1996) based on the original scale, and the quality of life scale developed by Ro (1988). The data were analyzed using descriptive statistics, pearson correlation coefficient, and stepwise multiple regression. Results: 1. The relationships among self-care, self-care agency, self-efficacy, and quality of life were significant. Self-care was significantly related to self-care agency (r=.609. p<.01), self-efficacy (r=.763. p<.01), and quality of life (r=.493. p<.01). 2. The stepwise multiple regression analysis was performed to identify factors influencing quality of life of the subjects. The most powerful predictor was self-care agency (48.4%). The combination of self-care, complication status, age, education level, and self-efficacy accounted for 88.7% of the variance of quality of life in type II diabetic patients. Conclusion: The results suggest that self-care, self-care agency, self-efficacy, and quality of life are important variables for development of nursing intervention programs for patients with diabetes.