Today, metal nanoparticles are being incorporated into soil through several routes, where they could alter the sorption behavior of other contaminants such as pesticides. Therefore, a short assay was carried out through sorption isotherms to evaluate the effect of copper nanoparticles (NCu) and copper sulfate (as the bulk form) at 50, 100, and 200 mg kg −1 on the sorption capacity of two commonly applied fungicides (carbendazim and iprodione) onto two agricultural soils, contrasting in organic matter content (2% and 14%) and texture (sandy and loamy) respectively. The isotherms were well described using the Freundlich model (R 2 > 0.95). Interestingly, at low organic matter, the pesticide sorption was notoriously increased in the presence of copper. However, NCu caused a minimal dose-dependent effect compared with their bulk form. Conversely, at high organic matter, the sorption was slightly altered by the presence of NCu. These findings constitute the first evidence that copper nanoparticles applied to agricultural soils can modify the sorption behavior of fungicides, which might increase their permanence in the environment. However, more detailed studies should be carried out in order to understand the interaction mechanisms between NCu/pesticides/ soil and consequently their potential environmental risks.