To date, sheep breeding in the Russian Federation is a promising branch of agriculture, in this regard, one of the priorities is to increase the number of livestock. First of all, agro-industrial complexes, farms of the Russian Federation engaged in breeding certain breeds of animals, not infrequently encounter diseases of the gastrointestinal tract of non-infectious etiology. On the basis of the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine, we examined 16 corpses of sheep of the Edilbaevsky breed aged from 10 days to 14 months. Cadaveric material was obtained during slaughter from the farm "Slaughter point" IP Yusubov O.M. located in the Vsevolozhsky district of the Leningrad region. The cadaverous material for the study was the pre-ventricles of small cattle, namely a omasum. In the course of the study, histological and morphological data were obtained and processed, as well as the features of the histostructures of the book wall in sheep of the Edilbaevsky breed in the age aspect were revealed. In our study, a complex of traditional histological methods and staining was used: hematoxylin-eosin and Masson trichrome. The purpose of our study is to study the histological structure of the omasum wall in sheep of the Edilbaevsky breed in the age aspect, to clarify morphometric indicators and to characterize the histostructures of this organ. Thus, during the study, it was found that the wall of the omasum in sheep of the Edilbaev breed developed evenly, and was not accompanied by a slowdown in its differentiation throughout the studied period of postnatal ontogenesis. This pattern is associated with the glycogen-depositing and transport functions of the mucous membrane and the high contractile function of the muscular membrane of the laminae omasi.