Idiopathic chronic pancreatitis accounts for up to one third of chronic pancreatitis cases. The most common inherited disease of the exocrine pancreas is cystic fibrosis, which is caused by mutations of a gene encoding an ion transport protein. It was discovered during the past year that many patients with idiopathic chronic pancreatitis have mutations of the gene that causes cystic fibrosis. This article reviews the evidence associating mutations of this gene with chronic pancreatitis and discusses the implications of this association for the evaluation, pathogenesis, classification, and possible prevention of pancreatitis.