Three Gram-negative, rod-shaped, oxidase-positive, aerobic, non-motile bacterial strains, designated H9T, H10 and H15, were isolated during a study on the diversity of culturable psychrotolerant bacteria in raw cow's milk. Comparisons of 16S rRNA gene sequences showed that the three strains were very closely related to each other (sequence similarities of 99.6-99.8 %). A polyphasic taxonomic study of the isolates resulted in their identification as members of the genus Chryseobacterium (family Flavobacteriaceae, phylum Bacteroidetes). The three strains showed < or =96.9 % sequence similarity with respect to the type strains of described Chryseobacterium species, indicating that H9T, H10 and H15 represent a novel species of the genus Chryseobacterium. The three strains grew at 7-37 degrees C (strain H10 grew at up to 41 degrees C), with 0-2.5 % NaCl and at pH 5.0-9.8. The dominant cellular fatty acids of strain H9T were 15 : 0 iso (38.9 %), 15 : 0 anteiso (15.6 %) and 17 : 0 iso 3-OH (12.7 %). Strain H10 also possessed 17 : 1 iso omega 9c (14.8 %) as a major fatty acid. On the basis of phenotypic properties and phylogenetic distinctiveness, the three milk isolates represent a novel species in the genus Chryseobacterium, for which the name Chryseobacterium bovis sp. nov. is proposed. The type strain is H9T (=LMG 24227T =DSM 19482T).