Advances in the therapy of type 2 diabetes mellitus (DM) have generated oral glucose-lowering agents that target different pathophysiologic processes in type 2 DM. Based on their mechanisms of action, glucose-lowering agents are subdivided into agents that increase insulin secretion, reduce glucose production, increase insulin sensitivity, and enhance GLP-1 action. It is also possible to classify these drugs into the proven or new. In this lecture, I would like to summarize and compare the strength and weakness of the proven (esp, sulfonylurea and metformin) or new drugs (esp, incretin related drugs).