An alkaliphilic actinomycete, strain YIM 80305(T), which was isolated from a muddy sample in Chaka salt lake, Qinghai Province of China, was characterized using a polyphasic approach. The isolate produced light-yellow substrate and yellow-white aerial mycelia on most tested media. Optimum pH for growth was 9.0-10.0 with scant growth at pH 7.0. Results showed that strain YIM 80305(T) was obligately Na(+)-dependent, and showed sensitivity to K(+). The DNA G + C content was 70.5 mol%. 16S rRNA gene sequence analysis together with these characteristics consistently assigned strain YIM 80305(T) to the genus Streptomyces. It formed a distinct clade based on analyses of the almost-complete and 120-nucleotide variable gamma region of the 16S rRNA gene. It could be differentiated by phenotypic and genotypic analysis from all the Streptomyces species whose names have been validly published. On the basis of polyphasic evidence, Streptomyces sodiiphilus sp. nov. is proposed. The type strain is YIM 80305(T) (= CCTCC AA 203015(T) = CIP 107975(T)).