A Gram-positive, coccoid, non-endospore-forming actinobacterium (strain CCUG 35676(T)) was isolated from cerebrospinal fluid from a 24-year-old woman in Gothenborg, Sweden. Based on pairwise 16S rRNA gene sequence similarity studies, strain CCUG 35676(T) was shown to belong to the genus Dietzia and was most closely related to the type strains of Dietzia aerolata (99.3%), Dietzia lutea (98.8%), Dietzia schimae (98.5%), Dietzia maris (98.5%), Dietzia alimentaria (98.3%) and Dietzia cercidiphylli (98.0%). The major menaquinone was MK-8(H(2)). Major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, an unidentified aminophospholipid (APL1), an unidentified phospholipid (PL1) and unidentified glycolipids (GL1 and GL3). Numerous other lipids were also detected. The fatty acid profile, comprising C(16:0), C(17:0,) C(18:1)ω9c and 10-methyl-C(18:0) as major fatty acids, supported the affiliation of strain CCUG 35676(T) to the genus Dietzia. On the basis of the results of physiological and biochemical tests and DNA-DNA hybridizations, a clear phenotypic and genotypic differentiation of strain CCUG 35676(T) from the most closely related Dietzia species is possible. Strain CCUG 35676(T) represents a novel species, for which the name Dietzia aurantiaca sp. nov. is proposed, with CCUG 35676(T) (=JCM 17645(T)) as the type strain.