The aim of this doctoral dissertation was to investigate neurotoxic potential of selected nanomaterials (NMs), silver, cerium (IV) oxide, and titanium dioxide, in two terrestrial invertebrates, honey bee Apis mellifera carnica and isopod Porcellio scaber. Organisms were exposed in chronic feeding tests, in which survival, feeding behaviour, avoidance, and other behavioral changes were monitored. Exposure was followed by additional analyses of selected biochemical biomarkers, surface adsorption of NMs (honey bees) and total elemental body concentration (isopods). Neurotoxic potential of NMs was studied through the effect on the cholinergic system, which is important neurotransmitter system in honey bees and isopods. More specifically, we analysed the activity of enzyme acetylcholinesterase (AChE) in salt-soluble and detergent-soluble fractions in different body compartments of honey bees (heads, thoraces, and haemolymph) and in whole isopods. In honey bees additional characterisation of AChE was performed in vivo with the use of specific AChE inhibitor diazinon; as well as in vitro with the use of native polyacrylamide gel electrophoresis in non-denatured conditions followed by specific AChE staining. Most metal and metal oxide NMs can cause oxidative stress therefore the activity of glutathione S-transferase was analysed as biomarker of detoxication. Additionally, protein content was analysed to assess the metabolic state of organisms due to energy-demanding compensatory and detoxication mechanisms. Finally, different behavioral tests were carried out with both test organisms, in which they were given a simultaneous choice between two qualities of the food or soil (isopods). With these tests we tested the exploratory and feeding behaviour of both organisms, as well as their ability to detect contaminated food or soil (isopods) and to select between untreated and contaminated food or soil (isopods) (that is to show preference or avoidance towards tested chemical).