A novel Gram-positive, rod-shaped, motile, spore-forming, nitrogen-fixing bacterium, designated strain 112(T), was isolated from cabbage rhizosphere in Beijing, China. The strain was found to grow at 10-40 °C and pH 4-11, with an optimum of 30 °C and pH 7.0, respectively. Phylogenetic analysis based on a fragment of the full-length 16S rRNA gene sequence revealed that strain 112(T) is a member of the genus Paenibacillus. High levels of 16S rRNA gene similarities were found between strain 112(T), Paenibacillus sabinae DSM 17841(T) (97.82 %) and Paenibacillus forsythiae DSM 17842(T) (97.22 %). However, the DNA-DNA hybridization values between strain 112(T) and the type strains of these two species were 10.36 and 6.28 %, respectively. The predominant menaquinone was found to be menaquinone 7 (MK-7). The major fatty acids were determined to be anteiso-C(15:0) and C(16:0). The major polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and unknown aminophospholipids. The cell wall peptidoglycan was found to contain meso-diaminopimelic acid. The DNA G+C content was determined to be 55.4 mol%. On the basis of its phenotypic characteristics, 16S rRNA gene sequence analysis and the value of DNA-DNA hybridization, strain 112(T) is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus brassicae sp. nov. is proposed. The type strain is 112(T) (= ACCC 01125(T) = DSM 24983(T)).