A moderate halophile, strain X50$^T$, was isolated from mustard kimchi, a traditional Korean fermented food. The organism grew under conditions ranging from 0-15.0% (w/v) NaCl (optimum: 3.0%), pH 7.0-10.0 (optimum: pH 9.0) and 15-45$^{circ}C$ (optimum: $37^{circ}C$). The morphological, physiological, and biochemical features and the 16S rRNA gene sequences of strain X50$^T$ were characterized. Colonies of the isolate were creamcolored and the cells were rod-shaped. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain X50$^T$ belongs to the genus Oceanobacillus and is closely related phylogenetically to the type strain O. iheyensis HTE831$^T$ (98.9%) and O. oncorhynchi subsp. oncorhynchi R-2$^T$ (97.0%). The cellular fatty acid profiles predominately included anteiso-$C_{15:0}$ and iso-$C_{15:0}$. The G+C content of the genomic DNA of the isolate was 37.9 mol% and the major isoprenoid quinone was MK-7. Analysis of the 16S rRNA gene sequences, DNA-DNA relatedness and physiological and biochemical tests indicated genotypic and phenotypic differences among strain X50$^T$ and reference species in the genus Oceanobacillus. Therefore, strain X50$^T$ was proposed as a novel species and named Oceanobacillus kimchii. The type strain of the new species is X50$^T$ (=JCM 16803$^T$ =KACC 14914$^T$ =DSM 23341$^T$).