In many organisms, the multixenobiotic resistance mechanism (MXR) is mediated by the activity of ABC transporters that bind and actively effl ux different toxic substrates from cells. This study attempted to identify MXR-related genes in the earthworm Eisenia fetida and compare the impact of the selected modulators, including verapamil, cyclosporine A, MK571, probenecid, orthovanadate, bisphenol A, and snow samples on the earthworm’s MXR. To confi rm the presence of MXR-reversing agents in E. fetida, we measured the accumulation of model substrates rhodamine B and rhodamine 123 in the body tissue of an adult earthworm. Experiments performed using the fi lter paper contact test showed that all of the tested modulators and environmental samples signifi cantly inhibited transport activity of the model substrates. Furthermore, partial mRNA sequence coding for P-glycoprotein (P-gp/Abcb1) was identifi ed and showed a high amino acid identity (up to 78 %) with homologues from different organisms. We could say that the ABC transporters are involved in various specifi c mechanisms that help earthworms to survive in a polluted environment and that their effi ciency can become compromised by environmental contamination.