An endospore-forming, rod-shaped bacterium was isolated from the rhizosphere of willow roots in Korea. The bacterium, designated strain BR030T, was a strictly aerobic, motile rod. The cell wall contained type A1gamma peptidoglycan with meso-diaminopimelic acid as the diagnostic diamino acid. The major cellular fatty acids were anteiso-C(15 : 0), iso-C(15 : 0), iso-C(14 : 0) and iso-C(16 : 0). The major cellular phospholipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and unknown phospholipids (PL1, PL2). The genomic DNA G+C content was 36 mol%. Comparative 16S rRNA gene sequence analyses showed that strain BR030T formed a distinct phyletic line within the genus Bacillus and was most closely related to Bacillus flexus DSM 1320T, with 16S rRNA gene sequence similarity of 96.8 %. Sequence similarities to other type strains were lower than 96.2 %. On the basis of physiological and molecular properties, the isolate represents a novel species within the genus Bacillus, for which the name Bacillus koreensis sp. nov. is proposed. The type strain is BR030T (= KCTC 3914T = DSM 16467T).