Apoptosis plays an important role in the normal physiology of the pancreas, the pathogenesis of diabetes mellitus (DM) and the success rate of islet transplantation. Glucagon-like peptide-1 (GLP-1), an incretin hormone with multiple effects on glucose metabolism and pancreatic gene expression, has recently been found to have antiapoptotic properties. This new property of GLP-1 has clinical relevance for the treatment of patients with overt DM, possible prevention of DM during the stage of impaired glucose tolerance and improvement in the outcome of islet transplantation. The pleiotropic effects of GLP-1 have fostered considerable interest in evaluating the efficacy of GLP-1, and might lead in the near future to its use in the prevention and/or treatment of DM.