Five coagulase-negative, novobiocin-susceptible staphylococcal strains were isolated from human blood cultures in different German and Belgian medical facilities. A novel species, 'Staphylococcus pettenkoferi' was proposed recently to accommodate two of these strains (B3117(T) and A6664), although the name was not validly published. All five strains belonged to the genus Staphylococcus because they were non-motile, Gram-positive, catalase-positive cocci with peptidoglycan type (A3 alpha type L-lys-gly(2-4)-L-Ser-Gly), menaquinone pattern (MK-7, MK-6 and MK-8) and major cellular fatty acids (ai-C(15 : 0), ai-C(17 : 0) and i-C(15 : 0)) that corresponded to those of staphylococci. Phenotypically, the isolates most closely resembled Staphylococcus capitis subsp. capitis and Staphylococcus auricularis, but they could be distinguished from these species by physiological tests and chemotaxonomic investigations. The results of DNA-DNA hybridization, chemotaxonomic investigations and 16S rRNA gene and RNA polymerase B gene (rpoB) sequence analysis enabled strains B3117(T), K6999, 229 and 230 to be differentiated genotypically and phenotypically from known Staphylococcus species, indicating that these isolates are representatives of a novel species. The name Staphylococcus pettenkoferi sp. nov. is proposed for this novel species, with strain B3117(T) (=CIP 107711(T)=CCUG 51270(T)) as the type strain. Due to differences in the results of physiological and chemotaxonomic investigations and DNA-DNA hybridization data, strain A6664 was not included in the description of the novel species.