A Gram-negative-staining, rod-shaped bacterium, designated strain SY01(T), was isolated from tidal flat sediment from Sacheon Bay, South Korea. Strain SY01(T) was characterized with respect to its phenotypic and phylogenetic characteristics. The novel strain was spore-forming, motile, catalase-negative and oxidase-positive. Optimal growth of the strain occurred at 30 °C and pH 7.0. The DNA G+C content was 56.1 mol%. The predominant menaquinone was MK-7. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and several unknown lipids were detected in the polar lipid profile. Anteiso-C(15 : 0) (47.2 %), iso-C(15 : 0) (18.9 %) and iso-C(16 : 0) (10.5 %) were the major cellular fatty acids of strain SY01(T). The highest 16S rRNA gene sequence similarities were found with Paenibacillus phyllosphaerae PALXIL04(T) (95.9 %), Paenibacillus tarimensis SA-7-6(T) (94.6 %) and Paenibacillus mendelii C/2(T) (94.4 %). Based on the phylogenetic, chemotaxonomic and physiological characteristics presented in this study, strain SY01(T) represents a novel species of the genus Paenibacillus, for which the name Paenibacillus sacheonensis sp. nov. is proposed. The type strain is SY01(T) ( = DSM 23054(T) = KACC 14895(T)).