Sigma receptors are originally detected in the nervous system, but they are also found in various other tissues, including the kidney. Previous studies indicate the renoprotective activity of σ1R, which is mostly mediated by modulation of the nitric oxide signaling pathway. Considering the importance of this signaling pathway in the pathogenesis of diabetic nephropathy, it could be assumed that σ1R have an important role in the pathogenesis of this condition. The purpose of the study was to investigate changes in the expression of σ1R in the kidneys, which could indicate their possible role in the pathogenesis of diabetic nephropathy. The research was carried out on Sprague Dawley rats. The type 1 diabetes mellitus was induced by the injection of streptozotocin (55 mg/kg). Rats with blood glucose level >16.5 mmol/L on the 4th day following the induction of diabetes were included in the experiment. The animals were sacrificed 2 weeks or 2 months after diabetes induction and a kidney tissue sample was harvested. The tissue was embedded in paraffin and 5 µm thick section were made, and stained with histological technique PAS and immunofluorescence method. Stained sections were photographed, and the resulting images were analyzed using ImageJ. For statistical analysis, a one-way variance analysis (ANOVA) and a Tukey test for multiple comparisons were used (GraphPad Software, La Jolla, CA, USA). In the kidney of the diabetic group of rats 2 months after injection of STZ, pathological changes characteristic for diabetes nephropathy were apperent, including: the expansion of mesangium, tubular sclerosis, the accumulation of hyaline material in the walls of the blood vessels and the vacuolization of distal tubule cells. The number of σ1R immunoreactive distal tubules in the control gruops decreased with time, while in diabetic groups it increased (both P<0.001). The number of immunoreactive tubules was significantly lower in the diabetic group 2 weeks after STZ injection when compared to the corresponding control group (P<0.01); while the number of σ1R positive tubules was significantly higher in the diabetic group 2 months after the induction of diabetes in comparison to the corresponding control group (P<0.001). The area of σ1R immunoreactivity was significantly higher in the diabetic group 2 months after the induction of diabetes compared to the control group, but also in comparison with the diabetic group 2 weeks after the induction of diabetes (both P<0.01). In vacuolated distal tubule cells of diabetic rats 2 months after injection of STZ, colocalization of σ1R and inflammatory growth factor TGFβ was observed. Our research has shown the strongest expression σ1R in the distal tubules in kidney of the rats. The dynamics of the expression of these receptors indicate their role in postnatal etiology of kidney maturation and in the development of diabetic nephropathy, in particular in the damage of distal tubules.