A natural focus of Dobrava hantavirus was first revealed in an arid zone of the Astrakhan Region, by using molecular genetic methods. A polymerase chain reaction was employed to examine 389 lung tissue suspension samples taken from 9 species. Hantavirus RNA was found in 35 samples from 22 field mice (Apodemus agrarius), 8 tamarisk gerbils (Meriones temariscinus), 4 common voles (Microtus arvalis), and 1 house mouse (Mus musculus). Sequencing determined the taxonomic affiliation of 18 new isolates to the Dobrava species and 1 isolate to the Puumala species although the new Dobrava isolated greatly differed from all known strains of this virus in the nucleotide sequence of the genomic M and S segments. Hantavirus-infected rodents were found in 3 of 4 districts of the Astrakhan Region, located in the steppe and semidesert zones and at the intrazonal stations of the Volga-Akhtuba flood-lands. The high (up to 12%) hantavirus infection rates were ascertained in a tamarisk gerbil, the typical inhabitant of desert and semidesert ecosystems.