A clinicopathologic study was conducted on six patients with intraductal papillary neoplasms of the pancreas. The patients were of both sexes and their ages ranged from 64 to 79 years. Three patients had a long history of symptoms mimicking chronic pancreatitis. The tumors involved the main pancreatic duct in the head-body region either diffusely or focally. Histologic examination showed papillary proliferations of well-differentiated, mucus-secreting cells that occasionally stained for carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9). The proliferations filled the main pancreatic duct, and extended into smaller ducts in some cases. In three patients, the lesions contained foci of pronounced to severe cellular atypia and carcinoma in situ. None of our series or any similar cases reported in the literature has shown invasion into peripancreatic tissue, metastasis, or tumor recurrence after pancreatectomy. Because of their favorable prognosis, intraductal papillary neoplasms should be considered low-grade malignancies that must not be confused with the common ductal adenocarcinoma.