The effects of ecological real concentration of pesticide "Mospilan" (active substance - acetamiprid) on the status of oxidative stress biomarkers, neurotoxicity and metallothioneins' (MTs) characteristics of freshwater bivalve mussels Anodonta cygnea were investigated. The prooxidative changes (decrease of superoxide dismutase activity, reduced glutathione content, increase of content of lipid and proteins peroxidation products) and decrease of the MTs content in gills and especially in digestive gland in the experimental group were reflected, whereas acetylcholinesterase activity was not changed. The effect of acetamiprid induces the appearance of additional chromatographic MTs form.