A Gram-positive, facultatively aerobic, rod-shaped, non-motile, terminal spore-forming bacterium, designated strain G20(T), was isolated from soil collected in a mountain region of Suwon, South Korea. On the basis of 16S rRNA gene sequence similarity, this strain was shown to be related to Rummeliibacillus pycnus NBRC 101231(T) (97.4%) and Rummeliibacillus stabekisii KSC-SF6g(T) (95.7%). DNA-DNA hybridization studies showed 42% and 50% similarity of strain G20(T) with R. pycnus NBRC 101231(T) and R. stabekisii KSC-SF6g(T), respectively. The DNA G content of G20(T) was 37.8 mol%, the major cellular fatty acids were iso-C15:0 and anteiso-C15:0, and the predominant menaquinones were MK-7 and MK-8. On the basis of phylogenetic, chemotaxonomic, and phenotypic characteristics, we propose this strain to be a novel species and the third member of genus Rummeliibacillus. We suggest the name Rummeliibacillus suwonensis sp. nov. The type strain is G20(T) (KACC 17316(T) =KEMB 9005-003(T) =JCM 19065(T)).