The pancreas consists of two histologically distinct and functionally independent components, i.e., endocrine islets and exocrine acini. Cells in the endocrine islets produce hormones and regulate body metabolism via the blood circulation, while cells in the exocrine acini secrete digestive enzymes through the duct system into the duodenal lumen. The structure of the pancreas and its postnatal developmental changes in humans and laboratory rodents have been intensively reviewed in more recent publications (1-3). A similar review is lacking for the domestic animal species. This chapter focuses on morphological structure of the pancreas in pigs and its growth and structural changes during the postnatal period. Wherever possible, information derived directly from studies of pigs is used, or otherwise species origin of the data is defined. Comparisons with other domestic animal species are made when information is available.