Four motile spored strains were isolated from soil samples collected in Japan. The cultures formed long, narrow sporangia on short sporangiophores directly on the substrate mycelium. The sporangia develop singly or in clusters above the surface of the substrate. Each sporangium contains a single row of six or more motile spores. Glutamic acid, glucosamine, glycine, alanine and 3-OH-diaminopimelic acid are present in the cell wall; the whole-cell sugars are 3-O-methylmannose, rhamnose, mannose, arabinose, galactose, xylose and glucose; and the predominant menaquinones are 10(H4), 10(H6) and 10(H8). The diagnostic phospholipid is phosphatidylethanolamine. The acyl type of the muramic acid is glycolyl. The G+C content is 71 mol%. Mycolic acids are absent. The chemotaxonomic data indicate that these strains belong to the family Micromonosporaceae. Analysis of 165 rDNA sequences suggested that these organisms fall into a distinct clade within the family Micromonosporaceae for which a new genus, Virgosporangium gen. nov., is proposed containing the species Virgosporangium ochraceum sp. nov. (strains YU655-43T, YU793-41 and YU794-41) and Virgosporangium aurantiacum sp. nov. (strain YU438-5T).