Pancreatitis is an increasingly common and sometimes severe disease that lacks a specific therapy. The pathogenesis of pancreatitis is still not well understood. Calcium (Ca 2+) is a versatile carrier of signals regulating many aspects of cellular activity and plays a central role in controlling digestive enzyme secretion in pancreatic acinar cells. Ca 2+ overload is a key early event and is crucial in the pathogenesis of many diseases. In pancreatic acinar cells, pathological Ca 2+ signaling (stimulated by bile, alcohol metabolites and other causes) is a key contributor to the initiation of cell injury due to prolonged and global Ca 2+ elevation that results in trypsin activation, vacuolization and necrosis, all of which are crucial in the development of pancreatitis. Increased release of Ca 2+ from stores in the intracellular endoplasmic reticulum and/or increased Ca 2+ entry through the plasma membrane are causes of such cell damage. Failed mitochondrial adenosine triphosphate (ATP) production reduces re-uptake and extrusion of Ca 2+ by the sarco/endoplasmic reticulum Ca 2+-activated ATPase and plasma membrane Ca 2+-ATPase pumps, which contribute to Ca 2+ overload. Current findings have provided further insight into the roles and mechanisms of abnormal pancreatic acinar Ca 2+ signals in pancreatitis. The lack of available specific treatments is therefore an objective of ongoing research. Research is currently underway to establish the mechanisms and interactions of Ca 2+ signals in the pathogenesis of pancreatitis.