A new actinomycete strain, LM 042T, which was isolated from a gold-mine cave in Kongju, Republic of Korea, is described by phenotypic and genotypic characters. The organism formed short chains of non-motile spores and globose bodies from substrate mycelium. An aerial mycelium was absent. This organism was chemotaxonomically characterized by the presence of meso-diaminopimelic acid, rhamnose, xylose, glucose, mannose and ribose in whole-cell hydrolysates (a type II cell wall and a variant of sugar pattern D), a glycolyl type of muramic acid, DNA G+C content of 70.4 mol%, a type PII phospholipid pattern (phosphatidylethanolamine as a diagnostic nitrogenous phospholipid), a tetrahydrogenated menaquinone with 10 isoprene units as a major menaquinone, and fatty acid profiles predominated by iso-branched hexadecanoic acid, iso-branched pentadecanoic acid and heptadcenoic acid. A comparative analysis of 16S rDNA sequences indicated that this organism formed a distinct clade within the evolutionary radiation of the family Micromonosporaceae and clustered with members of the genus Catellatospora. The 16S rDNA similarity values between the isolate and its phylogenetic neighbours, the two subspecies of Catellatospora citrea and Catellatospora tsunoense, were 95.0-95.2% and 94.9%, respectively. An equidistant relationship was observed among the isolate, Catellatospora ferruginea and all other members of the Micromonosporaceae genera (levels of similarity 93.0-94.0%). The combination of physiological, chemotaxonomic and DNA-DNA hybridization data supported that this organism is a novel species of the genus Catellatospora, for which the name Catellatospora koreensis sp. nov. is proposed. The type strain is LM 042T (= IMSNU 50729T).