During our taxonomic study of motile actinomycetes, soil isolate RA 335 was found to form a blue substrate mycelium and aerial mycelia with motile arthrospores and to have lysine as the cell wall diamino acid. Actinoplanes caeruleus IFO 13939T (T = type strain) and "Actinoplanes azureus" IFO 13993T are known to have the same characteristics. Therefore, the taxonomic position of these three strains was studied. Aerial mycelia of these strains fragmented during the growth cycle and produced motile spores arranged in chains within the mycelia. Sporangia were not observed. The strains contained menaquinone 9(H4), had guanine-plus-cytosine contents of 69.9 to 72.1 mol%, and had D-glutamic acid, D- and L-serine, glycine, L-alanine, and L-lysine as cell wall amino acids (type A3 alpha). The taxonomic characteristics of these strains differ from those of the previously described motile actinomycetes. On the basis of morphological, physiological, and chemotaxonomic data and the results of DNA-DNA hybridization and comparative 16S rRNA studies, we propose a new genus, Couchioplanes, for these organisms. The type species is Couchioplanes caeruleus comb. nov. (type strain, IFO 13939), which is divided into two subspecies, Couchioplanes caeruleus subsp. caeruleus subsp. nov. (type strain, IFO 13939) for A. caeruleus IFO 13939T and strain RA 335 and Couchioplanes caeruleus subsp. azureus (type strain, IFO 13993) for "A. azureus" IFO 13993T.