We studied the species diversity and abundance of small terrestrial mammals in the spring and autumn period of 2016-2019 in four groups of habitats of the protected area “Sarykum barkhans” of the Dagestan Nature Reserve: barkhan, floodplain forest, ailant plantations, the territory of the cordon. During the study period, 10 species of terrestrial small mammals were recorded – E. roumanicus, C. suaveolens, C. leucodon, M. musculus, M. macedonicus, A. fulvipectus, C. migratorius, M. socialis, D. sagitta, D. nitedula. Apodemus and Mus mice are the dominant species in the studied area. Mice of Apodemus and M. macedonicus were registered for the first time in the territory of barchans. Indicator species of xerophilic ecosystems – C. migratorius, M. socialis, D. sagitta, were recorded locally, exclusively in the only biotope of barkhan. H. auritus, S. pygmaeus, A. major, M. arvalis, A. terrestris, R. norvegicus, M. tamariscinus, which were previously noted by several authors, were not registered (both traces of vital activity and animals themselves) in the studied area during the whole period of research (2016-2019). Seasonal and annual fluctuations of species diversity and abundance taking into account groups of biotopes and small mammal habitats were revealed.