In immunohistochemical research of pigs’ pan-creas from the birth till 3 years of post-natal onto-genesis it was revealed that in the glands there were restructurings. In endocrine islets β-endocrinocytes+ form a heterocellular zone in the first day after an animal’s birth. In 3 months the part of islets consists of hemocellular zone β- endocrinocytes + in the form of continuous weight. The other part of islets is with heterocellular zone. In 3 years the cells are located only in hemocellular zone that leads to the formation of mantle type is-lets. In 3 years the cells are located only in hemocellular zone that leads to the formation of mosaic islets. From 6 months to 3 years δ-endocrinocytes+ and PP-endocrinocytes + lie only on the periphery of islets and have identical move-ment in islets. Since the birth till 1 year of life of an animal δ-endocrinocytes + and PP-endocrinocytes+ are located only in the periphery of islets and have identical movement in islets. Since a year of post-natal ontogenesis in some islets there is a moving of cells to the center leading to the formation of is-lets of two types by 3 years of life of an animal. The first type is the islets with a mosaic arrangement of δ- and PP-endocrinocytes+, the second type is the islets of peripheral area of the δ- and PP-endocrinocytes+. In addition to endocrine islets β- α- δ- and PP-endocrinocytes+ visualized in the exocrine pancreas and were located in the loose connective tissue between the pancreatic acini, excretory ducts of gland. Isolated β- and α-endocrinocytes+ were located among exocrine pancreatic cells, forming acinoinsulin cells.