The primary treatment goal for patients with diabetes is to prevent the onset and progression of diabetic complications. To prevent cardiovascular events, patients must maintain optimal long-term glycemic control and avoid hypoglycemia. DPP-4 inhibition enhances endogenous incretin action, and promotes glucose dependent insulin secretion and optimal glucagon secretion. Thus, DPP-4 inhibitor can improve postprandial hyperglycemia, without causing hypoglycemia in patients with diabetes. In this section, a continuous glucose monitoring(CGM), a device able to measure a patient's blood glucose fluctuation levels continuously, was used to evaluate efficacy of DPP-4 inhibitors.