A nitrogen-fixing bacterium, designated strain T98(T), was isolated from rhizosphere soil of Forsythia mira. Phylogenetic analysis based on a fragment of the nifH gene and the full-length 16S rRNA gene sequence revealed that strain T98(T) was a member of the genus Paenibacillus. High levels of 16S rRNA gene similarity were found between strain T98(T) and Paenibacillus durus ATCC 35681(T) (97.0 %), Paenibacillus sabinae DSM 17841(T) (98.3 %) and Paenibacillus zanthoxyli DSM 18202(T) (96.8 %). Levels of 16S rRNA gene sequence similarity between strain T98(T) and the type strains of other recognized members of the genus Paenibacillus were below 97.0 %. Levels of DNA-DNA relatedness between strain T98(T) and P. durus ATCC 35681(T), P. sabinae DSM 17841(T) and P. zanthoxyli DSM 18202(T) were 27.6, 30.0 and 32.1 %, respectively. The DNA G+C content of strain T98(T) was 50.4 mol%. The major fatty acids were anteiso-C(15 : 0), C(16 : 0) and iso-C(16 : 0). On the basis of its phenotypic characteristics and levels of DNA-DNA hybridization, strain T98(T) is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus forsythiae sp. nov. is proposed. The type strain is T98(T) (=CCBAU 10203(T) =DSM 17842(T)).