The Syrian hamster is a suitable animal model for the study of pancreatic neoplasms of ductal origin. Therefore, the present study was performed to obtain basic information on the pancreas of this species in neonatal life and during the aging process. Scanning electron-microscopic (SEM) examination showed that the islets of Langerhans could not be seen in the pancreas at day 15 of gestation or shortly after delivery, but developed during the first 14 postnatal days and doubled their size by 4 weeks after birth. In hamsters over 1 year of age, the islets of Langerhans attain a diameter of approximately 300 µm. Cells of the acini in the fetal pancreas already contain zymogen-like granules, their final size is reached by 28 days postpartum. Age does not markedly affect the epithelial cell height of the pancreatic ducts. Small ducts are lined with cuboidal large ducts with a columnar epithelium. The epithelial height correlates with luminal size which increases with age. The luminal surface of the ductal epithelium shows varying forms and density of microvilli, and usually a single, centrally located cilium. Mucus-producing cells, identified by droplets which protrude onto the cell surface, are first seen in the common duct of 4-week-old hamsters and are prominent in adult animals