A novel moderately thermophilic bacterium, strain TH13T, was isolated from a hot spring in Kamchatka. It was found to be a Gram-positive, facultative aerobe; the straight, non-motile rods grew at 30-64 degrees C (optimum 54 degrees C). The isolate was positive for catalase and oxidase tests and reduced nitrate to nitrite, but was negative for H2S production and growth in more than 3% NaCl (w/v). The isolate grew at pH 7-8, but not at pH values higher than 9. The DNA G+C content was 43.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that strain TH13T was a member of the genus Anoxybacillus. DNA-DNA hybridization revealed a low relatedness (less than 30.2%) between the isolate and its close phylogenetic neighbours Anoxybacillus pushchinoensis and Anoxybacillus flavithermus. On the basis of phenotypic characteristics, phylogenetic data and DNA-DNA hybridization data, it was concluded that the isolate merited classification as a novel species, for which the name Anoxybacillus voinovskiensis sp. nov. is proposed. The type strain of this species is TH13T (=NCIMB 13956T=JCM 12111T).