A novel aerobic bacterium, designated strain LAM0705T, was isolated from the rhizosphere of Populus alba in the Peking University Third Hospital. Cells of strain LAM0705T were observed to be Gram-stain positive, motile, spore-forming and rod-shaped. The optimal temperature and pH for growth were found to be 30 °C and pH 7.5, respectively. Strain LAM0705T was found to be able to grow in the presence 0–5 % NaCl (w/v) (optimum 1.0 %). The major fatty acids of strain LAM0705T were identified as anteiso-C15:0, C16:0 and iso-C16:0. The dominant polar lipids were found to consist of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The cell wall peptidoglycan of strain LAM0705T was found to contain meso-diaminopimelic acid. The predominant menaquinone was identified as MK-7. The G+C content of genomic DNA was found to be 48 mol% when determined by the T m method. The 16S rRNA gene sequence similarity analysis indicated that strain LAM0705T is closely related to Paenibacillus agaridevorans DSM 1355T and Paenibacillus thailandensis KCTC 13043T with 97.8 and 96.1 % sequence similarity, respectively. The DNA–DNA hybridization value between strain LAM0705T and P. agaridevorans DSM 1355T was 47 ± 0.8 %. On the basis of its phenotypic, phylogenetic and chemotaxonomic characteristics, strain LAM0705T is concluded to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus populi sp. nov. is proposed. The type strain is LAM0705T (=ACCC 06427T = JCM 19843T).