The number of hospitalizations in children with acute and chronic pancreatitis is increasing and accounts for significant morbidity. Acute pancreatitis is a reversible event involving diffuse inflammation of the pancreas with variable involvement of other regional tissues, remote organs, or both, whereas chronic pancreatitis is a process that produces irreversible changes in the pancreatic structure and function. Mutations in the gene encoding cationic trypsinogen have recently been identified to be associated with hereditary pancreatitis. Genetic mutations in the pancreatic secretory trypsin inhibitor and the cystic fibrosis transmembrane conductance regulator have been described to play a role in the development of pancreatitis as well. Mutations in the cytokine target genes relating to regulation of inflammation are likely to be important in determining the severity of pancreatitis. These findings, along with the advances in cell biology, have contributed to a better understanding of the pathophysiology of pancreatic diseases.