Abstract. The present research paper provides new information on the influence of ZnO nanoparticles (50 nm and 100 nm) on the activity of antioxidant enzymes catalase and superoxide dismutase in yeasts Rhodotorula gracilis. The application of NP ZnO (<50 nm) in the concentrations of 10 ... 5010-50 mg/L induces an increase in the activity of calalase by 20-50% in the strain Rhodotorula gracilis CNMN-Y-03 and initiates a reduction of up to 33% in the Rhodotorula gracilis CNMN-Y-30. In the case of NP ZnO application (<100 nm), the stimulation of catalase activity is recorded in both strains studied. The impact of ZnO nanoparticles (50 and 100 nm) is manifested byin the significant increase of the antioxidant enzyme superoxide dismutase on the yeast strains Rhodotorula gracilis investigated.