Pancreatitis is a disease with increasing incidence which can be divided into an acute and a chronic form. In both acute and chronic pancreatitis, changes in plasma concentration of pancreatic polypeptide (PP) and its regulation have been reported. In daily clinical work a serologic test for the precise diagnosis and staging of acute and chronic pancreatitis is still desirable. Therefore, many studies have investigated plasma concentrations of PP in acute and chronic pancreatitis as a diagnostic marker and as a therapeutic option to treat pancreatogenic diabetes mellitus. Although the study results are presently inconclusive and potentially contradictory, the findings are nevertheless encouraging, and indicate that PP might have a role in diagnosis, grading and estimation of the prognosis of pancreatitis. Further data and prospective controlled studies are needed to judge whether PP is of clinical value for diagnosing, staging and predicting long-term outcome in acute and chronic pancreatitis.