A strain of a previously undescribed non-lipophilic coryneform bacterium was isolated from pleural fluids of a patient with chronic renal failure, stroke and pneumonia. Slow fermentative acid production from glucose, maltose and sucrose, and strong N-acetyl-beta-glucosaminidase activity were the most characteristic features of the bacterium. Chemotaxonomic characterization unambiguously indicated that the organism belonged to the genus Corynebacterium. The results of comparative 16S rRNA gene sequence analysis revealed that the isolate represented a new species within the genus, for which the name Corynebacterium thomssenii sp. nov. is proposed. The type strain is DSM 44276.