- Abstract - Objectives: We examined the effects of diabetes mellitus (DM) case management program developed by National Health Insurance Corporation in Korea. Methods: One trained nurse performed the case management for 30 DM patients recruited through the reimbursement information of National Health Insurance in a rural community. The case manager had four home visits and two telephone calls for 12 weeks. We evaluated the effectiveness of the program in terms of self-efficacy, self-care behaviors and glyco-metabolic control. Results: The self-efficacy score was significantly increased from 70.0 of pre-intervention to 80.5 of post-intervention (p<0.001). The self-care score was also significantly increased from 2.86 to 3.60 (p<0.001). The scores of its components such as nutritional care, self-test of sugar level, foot care, oral care, and aerobic exercise were significantly improved (p<0.001). However, the improvement of score in medication management was statistically marginal (p=0.071). The fasting blood sugar level and HbA1c level was significantly decreased from 128.6 mg/dl to 114.5 mg/dl (p<0.001) and from 6.78 % to 6.54 % (p<0.001) respectively. Conclusions: The case management program was effective to improve the self-efficacy and self-care behaviors, and to control blood sugar level in DM patients.