Aim: To study the effect of native and UV-activated GdYVO4:Eu3+ nanoparticles in different concentrations on the histological and biochemical indicators of kidney function. Materials and Methods: Male rats (6 groups) were orally administered a colloidal solution of nanoparticles at doses of 50, 100, and 200 µg/kg body weight (native and UV-activated). An intact animal group was included. Each group contained 6 individuals. Pathohistological examination of kidney tissue and biochemical analysis of blood and kidney tissue homogenate were performed. Statistical analysis was done using the Mann-Whitney test. Results: Yellow granules were found in the glomerular tissue and tubular epithelium of rats. Volume voids were seen in the renal cortex with a medium-sized renal artery. As nanoparticle doses increased, the number of functioning glomeruli decreased, and both atrophic and hypertrophic glomeruli with hyperplasia of capillaries appeared. Higher doses were associated with increased transamidinase activity, von Willebrand factor, creatinine, and urea levels in blood serum, along with a decrease in ATP and total protein in kidney tissue. UV pre-irradiation of nanoparticles enhanced dystrophy, tissue death, and glomerular atrophy, with more pronounced biochemical shifts. Conclusions: Pathohistological and biochemical analysis showed that oral administration of GdYVO4:Eu3+ nanoparticles caused kidney damage, worsening with increased doses. UV-activated nanoparticles exacerbated renal damage.