The phenotypic and genotypic properties as well as cell chemistry of an interesting actinomycete, which converted certain azacarbazoles into highly cytotoxic derivatives, were established. The strain was also compared with two similar Japanese actinomycetes of Kitasatosporia gen. nov. A great resemblance between the strains was observed. Apart from similar phenotypic properties they were characterized by contents of both L- and meso-DAP, glycine and galactose as the main cell wall components. They proved to have the same phospholipid, glycolipid and fatty acid patterns. The guanine-plus-cytosine contents of the deoxyribonucleic acids of the strains averaged 72.5 and there was a high degree of homology between the DNAs of the strains (approximately 80%). These data provide evidence that the Spitsbergen isolate and the Japanese actinomycetes belong to one genomic species.