Background: The appropriate management of diabetes mellitus(DM) can help reduce its relapse and economic burden, but the level of management of DM in Korea is reported to be insufficient. This study aims to identify the management level of DM by figuring out the HbA1c examination performance rate of the diabetics and analyzing the variation according to the characteristic of a diabetic. Methods: This study used the Korean National Health Insurance Database which includes E10-14(ICD-10 code) as a primary or secondary disease as of 2006. Study population is 1,892,062 diabetics excluding 393,784 patients with the first attack of DM in 2006, 33,440 diabetics who died in 2006, and 21,299 patients with DM having no record of ambulatory care among the 2,340,585 DM patients in total. Results: The HbA1c examination performance rate of all DM patients in our country is estimated to be 41.5% as of 2006 and shows variation according to the characteristic of individual DM patients. The highest performance odds was shown by the patients who were below 19 of age, insured for health insurance, attended more than 3 ambulatory care providers, made ambulatory care visits more than 10 times annually, attended a specialized general hospital as their main attending medical institution, had a record of hospitalization or had co-morbidity. Conclusion: This study propose that is necessary to make politic preparations for the appropriate management of diabetes at a national level, and particularly, the patients with advanced age, the ones dependent on Medical Aid, and the ones using hospitals or clinics, whose appropriate management seems vulnerable, demand a careful management.