Aim. To conduct a morphological study of the renal glomerulus in experimental diabetes mellitus and to study the pathomorphological features of the development of diabetic nephropathy. Methods. The study was carried out on 25 male Wistar rats. Modeling of diabetes mellitus was carried out by intraperitoneal injection of streptozotocin at a dose of 65 mg/kg. For more selective modeling of type 2 diabetes, the rats of the control group were intraperitoneally administered a solution of cytoflavin, calculated by the dosage of nicotinamide 115 mg/kg. In the comparison group 1 ml of physiological solution was administered in a similar manner. On day 28 of the experiment, the animals were euthanized under ether anesthesia, the kidneys were extracted, purified and washed with physiological saline. The material was fixed in a 10% neutral formalin solution. Using the morphometric method, the area of the renal glomeruli and the area of the capillary lumens were measured, and after special computer processing of digital photographs, the total area of the vascular bed in the glomerulus and the area of mesangium in the renal glomerulus were estimated. Results. After four weeks of experiment on rats with diabetes mellitus, some characteristic changes in the morphofunctional state of renal tissues developed: an increase of the area of renal glomeruli, thickening of the basement membrane of glomerular capillaries, an increase in the size of podocytes with a decrease of their number, and foci of nephrosclerosis. Conclusion. Based on the results of the study, characteristic pathomorphological phenomena in the kidneys of rats with experimental diabetes mellitus were recorded, which indicate the development of diabetic nephropathy.