A strain of a hitherto undescribed coryneform bacterium from human clinical material was characterized by phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequence analysis demonstrated the strain represents a novel and deep lineage within the genus Corynebacterium sensu stricto. Chemical analyses revealed the unidentified strain was unusual in that it lacked mycolic acids. Based on the phylogenetic and phenotypic distinctiveness of the unknown isolate, it is proposed that the bacterium be classified as a new Corynebacterium species, for which the name Corynebacterium kroppenstedtii sp. nov. is proposed. The type strain is CCUG 35717T.