The taxonomic status of two recently described phenetically distinctive groups within the genus Acinetobacter, designated phenon 1 and phenon 2, was investigated further. The study collection included 51 strains, mainly of clinical origin, from different European countries with properties of either phenon 1 (29 strains) or phenon 2 (22 strains). DNA-DNA hybridization studies and DNA polymorphism analysis by AFLP revealed that these phenons represented two new genomic species. Furthermore, 16S rRNA gene sequence analysis of three representatives of each phenon showed that they formed two distinct lineages within the genus Acinetobacter. The two phenons could be distinguished from each other and from all hitherto-described Acinetobacter (genomic) species by specific phenotypic features and amplified rDNA restriction analysis patterns. The names Acinetobacter ursingii sp. nov. (type strain LUH 3792T = NIPH 137T = LMG 19575T = CNCTC 6735T) and Acinetobacter schindleri sp. nov. (type strain LUH 5832T = NIPH 1034T = LMG 19576T = CNCTC 6736T) are proposed for phenon 1 and phenon 2, respectively. Clinical and epidemiological data indicate that A. ursingii has the capacity to cause bloodstream infections in hospitalized patients.