We present a case of a 27-year-old female suffering from chronic calcifying pancreatitis with diabetes mellitus. Radiographic examinations and exocrine pancreatic function tests revealed considerable dilatation of pancreatic ducts with large intraductal calculi and exocrine pancreatic insufficiency, respectively. Recent literature indicates that a decrease in the activity of pancreatic stone protein (PSP), which inhibits CaCO3 crystal formation in pancreatic juice, is closely related to the development of chronic calcifying pancreatitis. The patient had no apparent cause or family history of pancreatitis. We therefore investigated the possibility that alterations in the PSP gene might explain the chronic pancreatitis seen in this patient. Six exons of the PSP gene amplified by polymerase chain reaction were directly sequenced, but there was no apparent base mutation observed. Furthermore, Southern blot analysis revealed neither rearrangement nor deletion of the PSP gene in the genomic DNA of this case. However, this genetic approach will be useful for future study of the etiology of hereditary pancreatitis.