Five coccoid, Gram-positive strains were isolated from the air of the 'Virgilkapelle' in Vienna. A representative of these five strains, V-108T, shared 99.0 and 98.4% 16S rDNA sequence similarity, respectively, with Agrococcus jenensis DSM 9580 and Agrococcus citreus DSM 12453T. Colonies of the five strains were white when grown in the dark and turned yellow in the light. The strains displayed highly similar biochemical and physiological characteristics and showed only small differences in their protein patterns obtained after SDS-PAGE. Based on Fourier-transform infra-red (FT-IR) spectra, the five strains were grouped together and separated from the other members of the genus, A. jenensis and A. citreus. Chemotaxonomic characteristics analysed from selected members of the five isolates, including polar lipids, quinone systems, polyamine patterns, cell wall composition and fatty acid profiles, were in good agreement with those of the two species of the genus Agrococcus described to date. The G+C content of the genomic DNA was determined to be within the narrow range of 73.8-74.9 mol%. The results of DNA-DNA hybridization with A. citreus DSM 12453T and A. jenensis DSM 9580T, as well as differences in biochemical/physiological characteristics, peptidoglycan composition, fatty acids, polar lipid profiles and FT-IR spectra, demonstrated that the five isolates represent a novel species of the genus Agrococcus. The name Agrococcus baldri sp. nov. is proposed for the novel species, of which strain V-108T (= DSM 14215T = CCM 4953T) is the type strain.