Abstract: Glyphosate-based herbicides are the world’s most widely used agrochemicals. They are sold as formulations, which contain a combination of active ingredients and so called inert ingredients, included adjuvants. Additional adjuvants (most often surfactants) are commonly added to this formulation to the tank mix before application. Toxicological tests are carried out for the active ingredients, e. g. glyphosate, however relatively little is known about the effects of the resulting cocktail of chemicals on beneficial organisms and environment. We studied the effect of widely sold herbicide formulation alone, and with tank mixing surfactants and the surfactants alone on the predatory activity of Pardosa spiders. We found that pure surfactants as well as glyphosate-based herbicide and surfactants tank mixes significantly influence the predatory activity of Pardosa spiders, while glyphosate-based formulation itself did not have the effect.