Aim. To evaluate the toxicity and genotoxicity of Ag2S quantum dots that had been synthesized by the mycelium of the fungus Pleurotus ostreatus on Drosophila melanogaster. Methods. The toxicity of nanoparticles was determined by assessing the survival rate of imagos and larvae. Genotoxicity was studied in the reparation test. The influence of nanoparticles on the development of the D. melanogaster reproductive system was determined by evaluating the number of ovariols. Results. The toxic effects of ionic silver and the absence of such effects in biosynthetic Ag2S nanoparticles had been shown. The negative influence of biosynthesized Ag2S nanoparticles and biomaterials and ionic silver on the development of D. melanogaster reproductive system had been revealed. There was no genotoxic effect for all investigated specimens. Conclusions. Ag2S biosynthesized quantum dots do not have a toxic and genotoxic effects on D. melanogaster at the concentration of 1.5 mg/ml. However, the action of Ag2S (salt), the biological matrix Pleurotus and biosynthetic Ag2S nanoparticles leads to a decrease in the number of ovariols. Keywords: Ag2S nanoparticles, D. melanogaster, toxicity, genotoxicity.