A novel bacterial strain, designated LCJ02(T), was isolated on R2A agar from donkey (Equus asinus) milk powder and subjected to a taxonomic study using a polyphasic approach. Strain LCJ02(T) showed a Gram-negative reaction, was non-motile, non-spore-forming and possessed rod-shaped cells and yellow-pigmented colonies. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel isolate formed a cluster with several uncultured bacterial clones and with cultured members of the genera Hydrotalea, Sediminibacterium and Lacibacter (family Chitinophagaceae, phylum Bacteroidetes). The gene sequence similarities with respect to the type strains of recognized species from the above genera and other phylogenetic neighbours ranged from 89.3 to 92.9%. The G+C content of the genomic DNA was 49.2 mol%, the only isoprenoid quinone was MK-7 and the major fatty acids were iso-C(15:0), iso-C(17:0) 3-OH, iso-C(15:1) G and summed feature 3 (C(16:1)ω7c and/or iso-C(15:0) 2-OH). The major polar lipids of strain LCJ02(T) were phosphatidylethanolamine, two unidentified aminophospholipids, one unidentified aminolipid and five unidentified lipids. The results of physiological and biochemical tests allowed phenotypic differentiation of strain LCJ02(T) from its closest phylogenetic neighbours. On the basis of the evidence of this polyphasic study, isolate LCJ02(T) represents a novel genus and species in the family Chitinophagaceae for which the name Asinibacterium lactis gen. nov., sp. nov. is proposed. The type strain is LCJ02(T) ( =KCCM 90108(T) =JCM 18484(T)).