The taxonomic position of two actinomycete strains isolated from soil was studied. The isolates contained glutamic acid, alanine and meso-diaminopimelic acid as cell-wall amino acids and menaquinone MK-9(H4) and madurose in the whole-cell hydrolysate. Phylogenetic analysis revealed that the isolates belonged to the family Streptosporangiaceae, but not to any known genus, and formed a monophyletic cluster with Streptosporangium corrugatum. On the basis of morphological characteristics, phylogenetic analysis and DNA-DNA hybridization, the name Acrocarpospora gen. nov. is proposed for a new genus containing the isolates and Streptosporangium corrugatum, and Acrocarpospora pleiomorpha sp. nov. R-31T (= IFO 16267T), Acrocarpospora macrocephala sp. nov. R-55T (=IFO 16266T) and Acrocarpospora corrugata comb. nov. IFO 13972T are described.