The taxonomic position of a thermophilic actinomycete strain isolated from soil was examined using a polyphasic approach. The strain, designated CH-M-1035T, was assigned to the genus Streptomyces on the basis of chemical and morphological criteria. It formed Rectiflexibiles aerial hyphae that carried long chains of rounded, smooth spores. The almost complete nucleotide sequence of the 16S rRNA gene of strain CH-M-1035T was determined and its comparison with the 16S rDNA sequences of previously studied streptomycetes confirmed the assignment of the novel strain to the genus Streptomyces. Strain CH-M-1035T clustered with species belonging to the Streptomyces thermodiastaticus clade in the 1 6S-rDNA-based phylogenetic tree. However, the phenotypic properties of strain CH-M-1035T differed from those of the recognized species within this clade. Therefore, it is proposed that strain CH-M-1035T be classified as a novel species within the genus Streptomyces, as Streptomyces mexicanus (type strain CH-M-1035T =DSM 41796T =BM-B-384T =NRRL B-24196T).