The processes of microbially induced precipitation of calcium carbonates are widespread in natural environments and are an important part of the biogeochemical carbon cycle. These processes comprised the basis of new "biocementation" technologies, which are extensively developed within the last decade around the world. These technologies are aimed at creating new "self-healing" construction materials, as well as at maintaining the strength of various buildings and building structures. The optimal conditions for the formation of calcites are increased salinity and alkalinity of the environment, which aroused interest in the search for calcifying microorganisms in a variety of ecosystems, including extreme ones. At present, many strains of halophilic and halotolerant bacteria that induce calcination have already been isolated and tested in pilot industrial processes. Most of these bacteria have urease activity, which is the main contributor to the binding of calcium ions to insoluble calcium carbonate. A wide variety of natural ecosystems with optimal conditions for the development of calcifying urobacteria, as well as the economic demand for biocementation technologies, stimulate interest in the search for more and more novel strains of these microorganisms. One of the promising resources to be screened for such organisms is the ecosystem of the drying Aral Sea and the adjacent desert and semi-desert Aral region. Here we present the results of screening various extreme ecosystems of the Aral region for the presence of calcifying microorganisms. We obtained 28 pure cultures of heterotrophic aerobic bacteria from samples of plant residues and soils of the Aral Sea region, 4 of which have urease and calcifying activities, their activities were compared with those of the strains already used to create biocementing preparations. Phylotypes of potential calcifying microorganisms in microbial communities of desert soil, thermal waters, and bottom sediments of a salt lake have been detected by molecular technique, and a description of the phylogenetic diversity of these communities has been given. The obtained results indicated the wide distribution of calcifying microorganisms in the ecosystems of the South Aral region and highlighted the expediency of screening them for new biotechnologically relevant and strains of these organisms.