This is a review of current information concerning the role of hormones and the autonomic nervous system in the control of exocrine secretions of the pancreas. A greater emphasis has been placed on the role of hormones because of information accumulated during the last several years. With the development of radioimmunoassay techniques, it is now possible to correlate circulating hormone concentrations with biological function. The role of hormones has been discussed with the framework of the secretin-glucagon family, the cholecystokinin-gastrin family, and other proposed gastrointestinal hormones and related peptides. Gastrin, secretin and cholecystokinin-pancreozymin are three prime gut hormones that regulate pancreatic secretion. Other hormones that may have a role in pancreatic secretion include glucagon, vasoactive intestinal polypeptide, chymodenin, somatostatin, pancreatic polypeptide, motilin, and bombesin. Neural mechanisms play an important although not so succinct a role in the over-all control of exocrine secretion. A complex relationship exists between the parasympathetic nervous system and the release of the hormones and their effect on pancreatic acinar and duct cells.