Three human clinical strains (W9323T, X0209T and X0394) isolated from a lung biopsy, blood and cerebral spinal fluid, respectively, were characterised using a polyphasic taxonomic approach. Comparative analysis of the 16S rRNA gene sequences showed the three strains belong to two novel branches within the genus Kroppenstedtia: 16S rRNA gene sequence analysis of W9323T showed close sequence similarity to Kroppenstedtia eburnea JFMB-ATET (95.3 %), Kroppenstedtia guangzhouensis GD02T (94.7 %) and strain X0209T (94.6 %); sequence analysis of strain X0209T showed close sequence similarity to K. eburnea JFMB-ATET (96.4 %) and K. guangzhouensis GD02T (96.0 %). Strains X0209T and X0394 were 99.9 % similar to each other by 16S rRNA gene sequence analysis. The DNA–DNA relatedness was 94.6 %, confirming that X0209T and X0394 belong to the same species. Chemotaxonomic data for strains W9323T and X0209T were consistent with those described for the members of the genus Kroppenstedtia: the peptidoglycan was found to contain LL-diaminopimelic acid; the major cellular fatty acids were identified as iso-C15 and anteiso-C15; and the major menaquinone was identified as MK-7. Differences in endospore morphology, carbon source utilisation profiles, and cell wall sugar patterns of strains W9323T and X0209T, supported by phylogenetic analysis, enabled us to conclude that the strains each represent a new species within the genus Kroppenstedtia, for which the names Kroppenstedtia pulmonis sp. nov. (type strain W9323T = DSM 45752T = CCUG 68107T) and Kroppenstedtia sanguinis sp. nov. (type strain X0209T = DSM 45749T = CCUG 38657T) are proposed.