We attempted to study whether social support promotes self-efficacy and reduces stress responses of patients with diabetes in Yogyakarta, Indonesia. Diabetic outpatients at Dr. Sardjito Hospital voluntarily participated in a questionnaire survey. Data from 125 patients were subjected to analysis. The questionnaires included the scales and subscales of social support, self-efficacy, psychological stress response, and demographic measure. Data were analyzed by Spearman's rank correlation test to examine the relationships between parameters, Mann-Whitney U-test and Kruskal-Wallis test to compare the scales by characteristics, and structural equation modeling to explore the best-fit model. This study was performed in September 2003. It was found that augmentation of emotional support to patients significantly increased the 'active coping for the disease' and 'controllability of health', and that 'helplessness' was reduced significantly. Behavioral support affected only 'controllably of health'. Self-efficacy reduced stress response of the patients. It was also found that subjects who received support from their children significantly scored higher in perceived availability of social support than those without support from their children. To know their behavioral support better as well as emotional support may be one area to focus on in improving the health status of people with diabetes in Yogyakarta.