Objective: Hypoglycemia is increasing complication of diabetes as strict control of HbA1c levels was emphasized to diabetic patients. Longer duration of diabetes, older age, irregular intake of diet and intensive medical treatment for lowering HbA1c levels are the risk factors of hypoglycemia. Recently, new anti diabetic agents which rarely cause severe hypoglycemia were developed and have been used increasingly. We designed the retrospective study to identify the changes of anti diabetic medication trend and to reveal association with hypoglycemic event. Methods: We conducted retrospective analysis of medical records of 698 patients who visited as hypoglycemia to emergency center of Inha university hospital from august 1, 2009 to september 30, 2013. Individual characteristics, risk factors, blood chemistry including HbA1c levels, types of medication and length of hospital stay were obtained and then analyzed by annually. Results: 377 of patients were selected according to the inclusion criteria. A mean age was 69.5 ± 13.0 years and a mean disease duration was 14.1 ± 9.2 years. A mean HbA1c level was 6.93 ± 1.50 %. A mean blood glucose level as checked in the EMC was relatively high with 73.5 ± 84.5 mg/dL, because 18% of patients were given the glucose supplement before admission. Renal function of patients was relatively decreased with a mean serum creatinine level of 2.60 ± 2.74 mg/dL and with a mean eGFR of 50.1 ± 33.6 mL/min. 37.1% of patients took insulin and 55.4% of patients took sulfonylurea. DPP4 inhibitor was taken by 8% of total patients and proportion of DPP 4 inhibitor usage had increased annually from 2009 to 2013 (P < 0.001). Conclusion: Severe hypoglycemia is frequent in older diabetic patients, subjects with low HbA1c levels, or nephropathy. Therefore, personalized attention is warranted, especially in long-term diabetics with multiple comorbidities. Outcome was not different among patients with the different anti-diabetic drug.