A Gram-positive, aerobic, non-motile, rod-shapeds, catalase-positive, and oxidase-negative strain, designated Y49T, was isolated from sewage collected from Jilin Agricultural University, China. It grew at 20-40°C (optimum at 30°C), at pH 6.0-8.0 (optimum at 7.0) and at 0-1.0% sodium chloride (optimum at 0%). The major isoprenoid quinone was menaquinone-8 (MK-8) and the polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, four unidentified lipids, and two unidentified aminolipids. The peptidoglycan was meso-diaminopimelic acid. The cell-wall sugars were galactose, arabinose, and glucose. The fatty acids were C9:0, C16:0, C16:1 ω9c, C17:1 ω9c, C18:3 ω6c (6,9,12), C18:1 ω9c, and C18:0. The DNA G+C content was 51.4 mol%. Based on the 16S rRNA gene sequence analysis, the nearest phylogenetic neighbors of strain Y49T were Corynebacterium efficiens DSM 44549T (97.5%), Corynebacterium callunae DSM 20147T (97.2%), Corynebacterium deserti GIMN 1.010T (96.8%), Corynebacterium glutamicum ATCC 13032T (96.4%), and other species belonging to this genus (92.3-95.4%). The DNA-DNA relatedness value between strain Y49T and C. efficiens DSM 44549T, C. callunae DSM 20147T, C. deserti GIMN1.010T, and C. glutamicum ATCC 13032T was 25.5±2.0%, 21.1±1.0%, 16.5±0.5%, and 13.5±0.9%, respectively. Based on the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain Y49T represents a novel species of the genus Corynebacterium, for which the name Corynebacterium defluvii sp nov. is proposed. The type strain is Y49T (= KCTC 39731T =CGMCC 1.15506T).