BACKGROUND: Diabetes mellitus is a chronic disease requiring continuous treatment and vigorous self-management. Reinforcement of effective self management and diabetes education are important factors in successful treatment. The aim of this study was to evaluate the effectiveness of the current diabetes education program on blood glucose control, self-management, and self-efficacy of patients with type 2 diabetes mellitus. METHODS: A total of 592 patients with newly diagnosed or uncontrolled type 2 diabetes mellitus were recruited to the diabetes education program from January to December 2007. We surveyed 338 patients from April to July 2008. A total of 117 patients had biochemical examinations and completed a questionnaire about knowledge, self-management and self-efficacy of diabetes treatment (no education group (n = 23), education group (n = 94)). RESULTS: The total scores from the questionnaires and the results of laboratory data showed no differences between the two groups. However, there were significant reductions in hemoglobin A1c level in the education group, as compared with the no education group (P = 0.039). Although the score for knowledge about diabetes mellitus was significantly higher in the education group (P = 0.005), greater knowledge was not reflected in the self-management or self-efficacy of the patients. CONCLUSION: The current diabetes education program had no effect on the self-management or self-efficacy of patients with diabetes, although did show some degree of association with blood glucose control and diabetes knowledge level. We conclude that a more effective diabetes education program needs to be developed and applied to daily practice for the improvement ofself-efficacy in patients with diabetes mellitus.