A novel actinomycete, strain YIM 45681(T), which was isolated from soil in a suburb of Kunming, Yunnan Province, China, was subjected to phenotypic and genotypic characterization. The micro-organism, which produces short spore chains arranged in spirals on the aerial mycelium, was shown to have meso-diaminopimelic acid in the cell wall. The sugars present in whole-cell hydrolysates were ribose, xylose, galactose, madurose and glucose. The predominant menaquinones were MK-9(H(4)), MK-9(H(6)) and MK-9(H(2)). The phospholipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. The major fatty acids were iso-C(16 : 1) H, C(17 : 1) omega 8c, 10-methyl C(17 : 0) and C(16 : 0). A comparative analysis of 16S rRNA gene sequences indicated that the organism formed a distinct clade within the evolutionary radiation of the family Thermomonosporaceae, and that it was closely associated with members of the genus Actinomadura. A broad range of phenotypic and genetic data supported the suggestion that this organism represents a novel species of the genus Actinomadura, for which the name Actinomadura alba sp. nov. is proposed, with YIM 45681(T) (=DSM 45045(T) =CCTCC AA206005(T)) as the type strain.