An alkaliphilic, endospore-forming bacterium isolated from Brazilian soil was taxonomically studied and is proposed as a new Paenibacillus species. This organism (strain 324(T)) was particularly distinguishable from other Paenibacillus species by its ability to grow optimally at ph 10 and 40 degrees C. the DNA G+C content was 50.9 mol%. The diamino acid of the cell-wall peptidoglycan was meso-diaminopimelic acid. MK-7 was the predominant menaquinone and anteiso-C-15:0 was the major fatty acid. Levels of 16S rDNA similarity between strain 324(T) and other Paenibacillus species were 90.6-95.9 %. Phylogenetically, strain 324(T) formed an evolutionary lineage distinct from other species within the evolutionary radiation encompassing the genus Paenibacillus. Based on phenotypic and chemotaxonomic properties, and phylogenetic inference, it is proposed that strain 324(T) should be placed in the genus Paenibacillus as a new species, Paenibacillus campinasensis. The type strain of the new species is strain 324(T) (= KCTC 0364BP(T)).483833837