A novel agarase-producing, non-endospore-forming marine bacterium, WH0801(T), was isolated from a fresh seaweed sample collected from the coast of Weihai, China. Preliminary characterization based on 16S rRNA gene sequence analysis showed that WH0801(T) shared 96.1 % similarity with Agarivorans albus MKT 106(T), the type species of the genus Agarivorans. A polyphasic taxonomic study was conducted and confirmed the phylogenetic affiliation of strain WH0801(T) to the genus Agarivorans. Isolate WH0801(T) produces light-yellow-pigmented colonies; cells are Gram-stain-negative, straight or curved rods, which are motile with a single polar flagellum. Strain WH0801(T) grew in 0.5-5 % NaCl, with optimum growth at 3 % NaCl, and its optimal pH and cultivation temperature were 8.4-8.6 and 28-32 °C, respectively. Data from biochemical tests, whole-cell fatty acid profiling, 16S rRNA gene sequence studies and DNA-DNA hybridization clearly indicated that isolate WH0801(T) represented a novel species within the genus Agarivorans, for which the name Agarivorans gilvus sp. nov. is proposed. The type strain of Agarivorans gilvus sp. nov. is WH0801(T) (=NRRL B-59247(T) =CGMCC 1.10131(T)).