A Gram-positive, non-motile actinobacterium, designated YIM 65754T, was isolated from the stem of Artemisia annua L., collected from Yunnan province, south-west China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YIM 65754T comprised an evolutionary lineage within the genus Rhodococcus. The isolate clustered with Rhodococcus pyridinivorans PDB9T, Rhodococcus gordoniae W 4937T and Rhodococcus rhodochrous DSM 43241T, with which it shared 98.4, 97.9 and 97.8 % 16S rRNA gene sequence similarities, respectively. However, DNA-DNA relatedness demonstrated that strain YIM 65754T was distinct from its closest phylogenetic neighbours. The cell-wall peptidoglycan contained meso-diaminopimelic acid, arabinose, galactose, mannose and glucose (cell-wall chemotype IV). The major menaquinone was MK-8(H2) and the predominant fatty acids were C16:0 (27.83 %), iso-C15:0 2-OH and/or C16:1�s7c (20.21 %) and 10-methyl C18:0 (17.50 %). The DNA G+C content was 66.2 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic evidence, the isolate represents a novel species of the genus Rhodococcus, for which the name Rhodococcus artemisiae sp. nov. is proposed; the type strain is YIM 65754T (=CCTCC AA 209042T=DSM 45380T).