An organism’s behaviour is an important trait that can be affected by toxicological compounds. Behaviour is often one of the first traits to be affected and behavioural changes may even drive effects at the population level. Pesticides and pharmaceuticals have a potential to induce behavioural effects in a variety of organisms. Since it is impractical to test all mixtures of chemicals, modelling approaches are used to predict combined effects. The goal of this research is to examine the mode of action of combined exposure underlying behavioural mixture toxicity in the nematode Caenorhabditis elegans in order to strengthen model development/predictability.