Gram-positive, rod- or coccoid-shaped bacterial strains KSL-17T, KSL-18 and KSL-19 were isolated from an alkaline soil in Korea. They were subjected to analysis using polyphasic taxonomy. Strains KSL-17T, KSL-18 and KSL-19 grew optimally at pH 8.0 and 28 degrees C and in the presence of 0.5 % (w/v) NaCl. They were characterized chemotaxonomically as having ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, MK-8(H4) as the predominant menaquinone and iso-C(16 : 0) as the major fatty acid. Their DNA G+C contents were in the range 74.6-74.8 mol%. Strains KSL-17T, KSL-18 and KSL-19 were identical in terms of their 16S rRNA gene sequences and exhibited a mean level of DNA-DNA relatedness of 85-90 %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains KSL-17T, KSL-18 and KSL-19 formed a distinct phylogenetic lineage within the genus Nocardioides. The levels of 16S rRNA gene sequence similarity between the three strains and the type strains of Nocardioides species were in the range 92.6-95.2 %. On the basis of phenotypic, genetic and phylogenetic data, strains KSL-17T (= KCTC 19039T = DSM 16315T), KSL-18 and KSL-19 should be classified as members of a novel species of the genus Nocardioides, for which the name Nocardioides lentus sp. nov. is proposed.