Chronic pancreatitis (CP) is characterized by irreversible morphological and functional alterations of the pancreas presenting clinically with upper abdominal pain as well as exocrine and endocrine insufficiencies. CP is morphologically characterized by pancreatic head enlargement, calcifications of the parenchyma, cysts, and pancreatic stones. The most common etiological factor of CP in Western industrialized countries is alcohol abuse; less common factors include hereditary pancreatitis, CP due to metabolic disturbances, CP due to pancreas divisum or duodenal wall cysts, and idiopathic CP. The molecular alterations leading to the chronic inflammatory process are nor completely understood. Research during the last years, however, has elucidated that a number of growth factors and their receptors are overexpressed in CP, which is thought to contribute to the high degree of pancreatic fibrosis and to the proliferative potential of ductular cells in this disorder. In addition, gene mutations have been detected in a subgroup of CP samples underscoring the pre-malignant potential of CP. In this review we will summarize our current knowledge about pathogenic and molecular aspects of CP.