The understanding of pathogenesis of acute and chronic pancreatitis has benefited from the progress made in genetic investigations. The discoveries of the gain of function mutations of cationic trypsinogen gene (PRSS1) and the loss of function mutations of pancreatic secretory trypsin inhibitor (SPINK 1) or other potential defects in genes that regulate pancreatic secretory function or modulate inflammatory response to pancreatic injury has changed our current concepts on the pathogenesis of pancreatitis. Genetic factors play an important role in the susceptibility to pancreatic injury, severity and evolution of inflammatory process, leading in some cases to chronic inflammation and/or fibrosis. Acute pancreatitis is viewed as an event and chronic pancreatitis as a process, sequentially linked, reflecting a complex interaction between genetic and environmental factors.