Silver nanoparticles (AgNPs) demonstrate strong antimicrobial activity resulting in their wide-spread use in different applications, including medical ones. Despite of the fact that human exposure to nanosilver is constantly increasing, there is no many research dedicated for investigating their potential neurotoxic effects. Most of the previous studies on mechanisms of nanosilver neurotoxicity have used in vitro models. The aim of the present study was to determine whether this small-sized commercially available AgNPs induce ultrastructural and biochemical changes in brain of male adult rats. Rats were exposed orally to 10 ± 4 nm nanosilver in size for 14 days. Using transmission electron microscopy (TEM), nanosized granules were detected in brains of exposed rats. Besides, ultrastructural changes in cortical and hippocampal neurons were found. TBARs level was measured to assessed lipid peroxidation in homogenates from exposed animals and immunochemical analysis was used to measure the level of selected tissue markers of oxidative stress in brain. Supported by grant nr NN401619938.