An anthracycline-producing actinomycete (strain SF2303) was compared with two other anthracycline producers, Actinomadura carminata IFO 15903T and Nonomuraea roseoviolacea IFO 14098T, using morphological, physiological, chemotaxonomic and molecular-genetic criteria. The morphological and cultural characteristics of these three strains are similar. The physiological properties of strain SF2303 and N. roseoviolacea IFO 14098T are very similar, but are different from those of A. carminata IFO 15903T in the utilization of some sugars and the reduction of nitrate. Their chemotaxonomic properties [cell wall chemotype, IIIB; major menaquinone, MK-9 (III, VIIl-H4); phospholipid type, PIV; cellular fatty acids 10M-17:0/17:1 and iso-16:0 as major components and 2-hydroxy fatty acids as minor components; mycolic acid, absent] were identical and indicated that these three strains belong to the family Streptosporangiaceae. On the basis of 16S rDNA sequences and phylogenetic analysis, they were all included in the cluster formed by species of Nonomuraea. The levels of DNA relatedness between strain SF2303 and N. roseoviolacea IFO 14098T ranged from 71 to 78%; however, the levels of relatedness between the two strains and A. carminata IFO 15903T were lower (49-60%). Therefore, strain SF2303 was identified as a member of the species N. roseoviolacea and it is proposed that Actinomadura carminata Gauze et al. 1973 should be transferred to a new subspecies of the genus Nonomuraea Zhang et al. 1998 as N. roseoviolacea subsp. carminata comb. nov.