Current medical therapy of type 2 diabetes use drugs targeting either insulin resistance, as metformin and/or glitazones, or insulin secretion, as sulfonylureas or glinides. The incretin effect, mainly due to glucagon-like peptide 1 (GLP-1), enhances the post-meal secretion of insulin, but its potential pharmacological use is hampered by the very short half-life of GLP-1. The inhibition of dipeptidyl peptidase-4 (DPP-4), which inactivates GLP-1, has led to the development of a new class of antidiabetic molecules, the DPP-4 inhibitors, also known as gliptins. Sitagliptin is now commercially available, but many other gliptins are currently under clinical development. Their normoglycemic efficacy is moderate, with a mean HbA1c decrease by 0.7 to 1.1%, and they are well-tolerated, especially with a low risk of hypoglycaemia and no weight gain. In animal studies, they appear to preserve pancreatic β-cell function, by increasing β- cell mass and reducing apoptosis. The clinical significance of these properties requires confirmation by further long-term studies. DPP-4 inhibitors seem to represent an efficient and well-tolerated new class of oral normoglycaemic agents, with a potential beneficial effect on pancreatic function, but their real efficacy and safety have to be firmly assessed in the future, before they could find their appropriate place in the management of type 2 diabetes.