Soil is one of the less studied resources of terrestrial ecosystems, both in terms of its biodiversity and internal processes. In particular, microarthropods of desert ecosystems have been poorly studied worldwide, and probably less than 10% of the total soil species have been described. Nevertheless, microarthropods are responsible for one of the most important environmental functions: the decomposition of organic matter. In this chapter, we present the results of the first survey of soil microarthropod communities from the CCB. The study was conducted in 20152016 to identify the microarthropods' diversity in its components of richness and abundance. We collected 6721 organisms of 6 classes, 26 orders, and 60 families. Acari was the most abundant and diverse group and is dominated by Prostigmata (20 families) and Oribatida (16 families). Hexapoda is represented by Collembola, Coleoptera, Hemiptera, Hymenoptera, and Psocoptera. Differences in mite assemblages are attributable to the type of vegetation in the different sites of the CCB. The site's taxonomic diversity is associated with habitat heterogeneity. The high productivity micro-habitats could produce high levels of biomass and not necessarily more diverse communities. We observed broad similarities in microarthropod composition at familial level among arid-semiarid ecosystems elsewhere in the world. Knowledge of soil microarthropod community will be helpful to understand the network of interactions and the flow of nutrients and energy within this desert ecosystem; all these are crucial elements to assess the health of the soil and to establish appropriate strategies for it use, management, and conservation.