Chronic pancreatitis is a continuing inflammatory disease characterized by irreversible morphological change and, typically, by pain and permanent impairment of function. The pathogenesis of pancreatitis, either acute or chronic, is still controversial. There have been no widely accepted concepts to provide a reasonable explanation linking the known etiological factors and the pathophysiological aspects of the disease. Alcohol is undoubtedly the major etiological factor in most countries, and the relative importance of alcohol as a cause of chronic pancreatitis ranges from 40% to 90% in various countries. As fewer than 10% of alcoholics develop chronic pancreatitis, other nutritional or genetic influences are likely to be involved in the pathogenesis of alcoholic pancreatitis. Accessory pancreas incidentally found in patients with chronic alcoholic pancreatitis does not always have the pathological findings seen in the main pancreas. Integrity of the pancreatic duct seems to be another important factor for chronic alcoholic pancreatitis. Gene mutations of the cystic fibrosis transmembrane conductance regulator (CFTR), cationic trypsinogen, and pancreatic secretory trypsin inhibitor have been investigated in idiopathic chronic pancreatitis. Molecular and cell biology research during the past few years has elucidated pathophysiological factors that are involved in the pathogenesis of chronic pancreatitis, but cannot demonstrate a common pathway between etiological factors and the pathogenesis or development of the disease.