Introduction. Morbidity toxocariasis, second in prevalence geohelminthiasis in Russia, is a serious problem in recent years, especially in metropolitan areas. The involvement of earthworms in the life cycle of toxocarias remains poorly understood. The role of earthworms (paratenic hosts) in the circulation and prevention of toxocariasis is established. The work is aimed at a contribution finding out of earthworms Eisenia fetida (paratenic hosts) in toxocariasis circulation and prevention. Material and methods. Nematodes dehelminthization derived from animals. For the first time in Russian Federation, experiments have been conducted on infestation of earthworms E. fetida with infective eggs Toxocara canis and Toxocara mystax. Results. In the conducted experiments, possibility is proved of infestation of earthworms E. fetida with infective eggs T. canis and T. mystax via earth bacterized with 10000 infective eggs. For the first time migration was proved of ascaridate larvae from intestines to skin-muscular sac of the earthworms. Conclusion. Besides, investigation was conducted aimed at finding out of the period duration of T. canis and T. mystax larvae staying in earthworms' intestines and sinews. © 2019 Izdatel'stvo Meditsina. All rights reserved.