The most specialized and least studied ecological group of Myxomycetes are coprobionts species, found mainly in steppes and deserts. They develop on the weathered dung of herbivorous animals. At present, about 114 species of Myxomycetes are found on this substrate in the world, but only 16 of them are considered obligate coprobionts. We believe that species become optional coprobions due to the absence of characteristic types of substrata in habitats with extreme environmental conditions, and in this connection they develop on accessible substrates. For obligate coprobionts, dung is the only suitable substrate on which they can develop, which is due to a long adaptive evolution. We collected samples of substrates in various locations of the Altai Territory, the Novosibirsk Region, the Republic of Buryatia and the Republic of Altai to identify the Myxomycetes of the coprobionts complex using the moist-chamber method. Five obligate of the coprobionts species were identified: Didymium nullifilum (Kowalski) M.L. Farr, Kelleromyxa fimicola (Dearn. Et Bisby) Eliasson, Perichaena corticalis var. liceoides (Rostaf.) G. Lister, Perichaena luteola (Kowalski) Gilert and Trichia brunnea J. J. Cox. for the territory of Siberia. Of these, one species has been found for the first time for Russia, one for the Asian part of Russia, one species was recorded for the first time in the Altai Territory, the Novosibirsk Region, and the Republic of Buryatia. The substrate specialization and distribution of the identified species in the study area were investigated. The carried out researches have shown that the species considered obligate coprobionts, can develop also on the dead and alive parts of the higher vascular plants. It should be borne in mind that they probably hit the above substrate by migrating the plasmodium from a nearby dung, blurred by rain.