Traditionally, past wildlife habitat management on public lands has been restricted to game species. Recent policy now dictates that all BLM-administered lands are to be inventoried for nongame species. The first nongame inventory was completed during the spring and summer of 1978 on two planning units in central Arizona comprising some 338,000 acres of public land. Vertebrate species were surveyed for relative density, species diversity, and distribution. During the course of this study a total of 50 mammal species were either collected or observed. Trapping methods closely followed that of Calhoun (1951) and more than 18,000 trap nights were accumulated. Relative densities for 19 different species collected along trap lines were determined within eight plant communities of the Sonoran Desert. Distribution and density data clearly demonstrate the ability of mammal species to overlap habitat and reveal general trends as to habitat preference. Desertscrub and wash communities were the most productive habitats for small mammals. They supported the highest relative densities and the highest number of species. In contrast, the more mesic habitats, such as riparian woodlands and interior chaparral, were the least productive habitats sampled.