Glucagon-like peptide-1 (GLP-1) is one of the incretin hormones that are released by the enteroendocrine cells of the small intestine in response to food intake. One of the actions of these hormones is to stimulate insulin secretion in the presence of elevated levels of blood glucose. Studies have shown that GLP-1 may also have a range of other actions associated with glucose homeostasis, including regulation of insulin biosynthesis, inhibition of glucagon secretion, modulation of gastrointestinal motility and modulation of food intake. However, it has been shown that there is a deficient GLP-1 response in patients with impaired glucose tolerance or with type 2 diabetes mellitus. A number of studies presented at the 18th International Diabetes Federation (IDF) Congress [Paris, France; August 2003] discussed the effects of GLP-1 and its analogues in type 2 diabetes, and the cellular mechanisms involved in its actions.