The extensive Mongolian grasslands hosts a high variety of micro-habitats which wildlife uses as corridors that enable species to expand their range. Between May 2017 and March 2018, we conducted an intensive survey in the Mongolian-Manchurian Grassland Ecoregion using camera trapping, field transects, live trapping and opportunistic observations, in mountain outcrops, grass steppe and sand dune habitats across seasons. Our aim was to compile the first satisfactory inventory of mammals based on scientific methods for a diverse landscape in the Mongolian provinces of Tov and Dundgovi. Furthermore, our research seeks to fill in knowledge gaps on species distribution and range expansions in the endangered west Mongolian-Manchurian Grassland ecoregion and identify biodiversity hotspot areas encompassed in this biogeographic crossroad. We recorded 31 species of non-volant mammals, including a globally Endangered species and two Near Threatened species, according to the IUCN Red List, and three species listed in Appendix II of CITES.