The aim of the study was to study the features of the histological structure of the kidneys in sheep of the South Ural breed in the postnatal period of ontogenesis. The studies were carried out on the Department of Morphology of Physiology and Pathology of the Orenburg State Agrarian University. The material for the study was the kidneys of the South Ural breed sheep from 12 individuals of both sexes. Animals were divided into 2 age groups based on the classification of development periods. For histological examination, we took the material no later than two to three hours from the moment of slaughter of the animal. Pieces of tissue were fixed in a 10% solution of neutral formalin. After fixing and sealing, the pieces were poured into parafin. Histological sections 5-7 µm thick were stained with hematoxylin-eosin. On histological preparations, we determined the thickness of the connective tissue capsule, the cortex and the medullary layer, the diameter of superficial, intracortical and juxtamedullary nephrons, as well as the diameter of the vessels of the microvasculature of the kidneys. Morphometric parameters were obtained using a screw eyepiece-micrometer MOV-1-15x (GOST 15150-69) and an eyepiece ruler, followed by statistical processing of quantitative parameters of histological structures. In our study of histological preparations of the kidneys of day-old lambs, an organotypic morphology was revealed. Outside, the kidney is covered with a connective tissue capsule 42.5 ± 4.28 µm thick. The boundaries of the cortical and cerebral zones are clearly differentiated, in the cortical zone (thickness - 1575.0 ± 71.11 microns), numerous compact subcapsular and juxtamedullary renal corpuscles - glomeruli, proximal and distal convoluted tubules, as well as connective tissue trabeculae were visualized