This research deals with impacts of pesticide substances on spider populations. In this case pesticides of the neonicotinoids classes were tested. Specific neonicotinoids were applied to different of spiders which were collected in various localities and at some stage of development - nymph, adult or subadult individuals. The diploma thesis analyzes and the documents the effects of neonicotinoids to spiders. The results show that some pesticides can have a significant negative effect to locomotion, predation, ballooning, drop or to spiders mortality. Keywords: spider, arthropod, pesticides, insecticides, neonicotinoids, sublethal effects, mortality, EthoVision XT, locomotion, drop, ballooning, predation, Philodromus, Oedothorax, Pardosa, Xerolycosa, Phylloneta