A typification of Moscow city habitats is undertaken, based on their consideration as a mosaic of spaces and using such fundamental parameters as habitat origin (soil type), floristic structure and habitat area. Altogether, 11 habitat types are distinguished: lawns, agrocoenoses, xerophytic and mesophytic meadows, tall weeds, boulevards, small degrading parks, small oppressed artificial parks, landscape parks, forest parks and technocoenoses. Such a classification is primarily useful for studying the ants. The present paper describes the basic structure of ant complexes in most of the types of city biocoenoses. The main pool of Moscow's ant species ranked by their frequency is as follows: Lasius Niger (87%), Myrmica rugulosa (44%), Myrmica rubra (33%), Formica cunicularia (11%), Myrmica ruginodis (10%), etc. The effect of leaf litter removal with rooks on ant communities in forested areas is studied and shown to be negative to the numbers, biomass and species diversity. The most stable two-species ant community revealed in Moscow City, termed an "elementary urban community", consists of L. Niger and M. rugulosa, with the former species always outnumbering the latter one.