On the basis of the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine, we examined 10 corpses of sheep of the Edilbaevsky breed aged one year and older. The cadaveric material for the study was the preventricles of small cattle, namely, the rumen. In the course of the study, histological and morphological data were obtained and processed, as well as the features of the histostructures of the rumen wall of Edilbaevskaya sheep in postnatal ontogenesis were revealed. In our study, we used a set of traditional histological methods and staining: hematoxylin-eosin and trichrome Masson. The rumen, by its function, is a depot for the temporary preservation of incoming food from the oral cavity. In the rumen cavity, factors such as temperature, pH, and a certain ionic composition create optimal conditions for the development of microflora and the absorption of bacterial fermentation products. The normal physiological state of this part of the multicameral stomach is responsible for many indicators of the animal's productivity. Like the entire digestive tract, the rumen in sheep of the Edilbaevsky breed has three shells in its structure: mucous, muscular and serous. The surface of the mucous membrane of the scar is lined with a multi-layered flat epithelium of the skin type with papillary relief. In the mucous membrane of the muscle is no record in this regard, the loose connective tissue of the lamina propria submucosa goes into the Foundation without visible boundaries. Papillae are formed in postnatal ontogenesis, during the transition from milk feeding to coarse feeding. The muscular shell of the wall of the first pre-ventricle is represented by two layers of smooth muscle tissue: internal and external. Striated fibers are present at the entrance of the esophageal gutter to the scar. The serous membrane of the scar is represented by a loose fibrous connective tissue covered with mesothelium on the outside, as in other parts of the digestive tract.