Marine sediment was collected from the Yellow Sea, Korea, and enriched using 1 mM thiosulfate under aerobic conditions. After 2 weeks, a facultative sulfur-oxidizing strain, BR13, was isolated. Phylogenetic analysis based on the 16S rRNA gene sequence showed that this strain belonged to the genus Marinobacter in the gamma-proteobacteria and was most closely related to Marinobacter pelagius $H225^T$ (99.5% 16S rRNA gene sequence similarity) and Marinobacter koreensis DD-$M3^T$(97.7% 16S rRNA gene sequence similarity). The isolate was a sulfur-oxidizer, Gram-negative, aerobic, and slightly halophilic bacterium and grew in 0.5-9% NaCl at 7-$37^{circ}C$. Strain BR13 shared some physiological and biochemical properties with Marinobacter pelagius $H225^T$ and Marinobacter koreensis DD-$M3^T$. The G+C content of the genomic DNA of strain BR13 was 58.4 mol%. Strain BR13 possessed $C_{16:0}$, summed feature 4 ($C_{16:1}$ ${omega}7c$ and/or $C_{15:1}$iso 2OH), $C_{16:0}N$ alcohol, and $C_{18:1}$ ${omega}9c$ as the major cellular fatty acids. Our results showed that strain BR13 (=KCTC 22253 =JCM 15135) is a novel facultative sulfur-oxidizing strain in the genus of Marinobacter.