Abstract <p>The activity, qualitative and quantitative compositions of soil microbial communities, and their tolerance to heavy metals and polycyclic aromatic hydrocarbons are studied to develop the approaches for assessing the transformation of microbial communities in urban soils (Urbic Technosols). Anthropogenically transformed and natural soils were sampled in the territory of Rostov-on-Don (a large industrial city in the steppe zone) to determine soil physicochemical properties and to analyze soil microbiological characteristics. In anthropogenically transformed soils, Zn concentration somewhat exceeds the approximate threshold value (reaching 244 mg/kg) and benzo[<i>a</i>]pyrene concentration is considerably higher than the threshold limit value (up to 400 ng/g). The counts of streptomycetes and assessment of nitrification activity are the most sensitive indicators of anthropogenic load, being two–fourfold lower in urban soils. Although the abundances of other ecotrophic groups, such as copiotrophs, prototrophs, amylolytics, proteolytics, and denitrifiers, do not change, the composition of the microbial community in anthropogenically transformed soils shifts towards an increase in the share of pigmented microorganisms, including the actinobacteria able to degrade PAHs (<i>Kocuria, Gordonia,</i> and <i>Rhodococcus</i>) and tolerant to Cd. Thus, urbopedogenesis restructures microbial communities suggesting new bioindicators for assessing urban soils.</p>