A catalase-negative actinomycete, strain YIM 21741T, was isolated from a soil sample collected from a primeval forest at Xishuangbanna, Yunnan Province, China. Analysis of 16S rDNA showed the strain to be related to members of the genus Agromyces, with which it also shares morphological characteristics, e.g. branching hyphae breaking into diphtheroid and rod-like, irregular, non-motile fragments and a peptidoglycan containing the diagnostic amino acid 2,4-diamino-n-butyric acid. Whole-cell hydrolysates of strain YIM 21741T contained rhamnose and small quantities of glucose, galactose and mannose. The major menaquinone was MK-12, while MK-13 and MK-12 were minor components. Diagnostic phospholipids were phosphatidylglycerol and diphosphatidylglycerol. The G + C content of the DNA was 72.8 mol%. Physiological and biochemical characteristics reveal strain YIM 21741T to be different from all validly described species of the genus Agromyces. As DNA-DNA similarity values between this isolate and the phylogenetically neighbouring type strains of Agromyces bracchium and Agromyces luteolus are only moderate, the novel species Agromyces aurantiacus sp. nov. is proposed with strain YIM 21741T (=CCTCC 0010112T =AS 4.1717T =DSM 14598T) as the type strain.