The vast array of medications currently available for treating patients with T2DM has increased substantially. Current investigations clarified novel mechanisms underlying the pharmacokinetic and pharmacodynamic profiles as well as the antidiabetic efficacy of these agents. This article reviews the mechanisms of action of four medication groups currently approved for treating T2DM, with the exception of insulin and its analogues. The article also tries to integrate the mechanisms of the agents to the schema of the pathophysiological factors associated with hyperglycemia in T2DM patients.