Intraductal papillary mucinous neoplasm (IPMN) is a recently recognized clinicopathologic entity characterized by dilatation of pancreatic duct filled with copious mucin and papillary ductal epithelial proliferation ranging from simple hyperplasia to invasive carcinoma. The exact clinicopathologic identification of this tumor is important because of favorable prognosis contrast to that of conventional ductal adenocarcinoma. Herein we report a case of surgically resected typical IPMN. A 59-year-old man had a long history of diabetes mellitus with epigastric pain of 4 months duration. Ultrasonography and computed tomographic examination revealed cystic dilatations of main pancreatic duct in the head. The patient underwent total pancreatectomy. The gross appearance showed diffuse dilatation of main pancreatic duct associated with cystic dilatation of subbranches in the uncinate process. Histologic examination revealed diffuse papillary proliferations lined by mucinous epithelium with mild atypism within ectatic ducts. No invasive carcinoma was noted. Histochemically, the papillary epithelium contained mostly neutral and acid sialomucin.