Chromogranins are acidic secretory glycoproteins with a widespread but specific distribution in neuroendocrine tissues. The chromogranin family is heterogenous, consisting of propeptides such as chromogranin-A, chromogranin-B and secretogranin II, which can either elicit an effect themselves, or serve as precursors to a large number of peptides, which are biologically more active. Chromogranin processing varies in different neuroendocrine tissues. Furthermore, it is more marked in pancreatic islets than in many other tissues. Chromogranin-A and chromogranin-B are expressed in all types of pancreatic islet cells, whereas secretogranin II has not been found in pancreatic tissue. The aim of the present mini review is to focus on chromogranin-A, chromogranin-B and their derived peptides, in the function of pancreatic islets.