A Gram-staining positive, facultative aerobic bacterium, designated strain RH-N24(T), was isolated from naked barley in South Korea. Cells of the isolate were observed to be motile rods by means of peritrichous flagella and showed catalase-positive and oxidase-negative reactions. Growth of strain RH-N24(T) was observed at 4-40 °C (optimum: 35-37 °C) and at pH 5.0-9.0 (optimum: pH 6.0-7.0). Chemotaxonomic data (major isoprenoid quinone: MK-7; DNA G + C content: 53.5 mol %; cell wall type: A1γ-meso-diaminopimelic acid; major fatty acids: anteiso-CB(15:0) and CB(16:0B)) supported the affiliation of the isolate to the genus Paenibacillus. The major cellular polar lipids were identified as phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and two unidentified polar lipids. Phylogenetic analysis based on 16S rRNA gene sequences also supported the conclusion that strain RH-N24(T) belonged to the genus Paenibacillus. Comparative 16S rRNA gene sequence analysis showed that strain RH-N24(T) was most closely related to Paenibacillus hunanensis FeL05(T) and Paenibacillus illinoisensis NRRL NRS-1356(T) with similarities of 94.64 and 94.54 %, respectively. On the basis of phenotypic and molecular properties, strain RH-N24(T) represents a novel species within the genus Paenibacillus for which the name Paenibacillus hordei sp. nov. is proposed. The type strain is RH-N24(T) (=KACC 15511(T) = JCM 17570(T)).