A previously undescribed anaerobic, heterofermentative, non-spore-forming, Gram-positive rod was isolated from the hindgut of the Formosan subterranean termite Coptotermes formosanus Shiraki. The DNA G+C content of this bacterium was 37.8 mol%. Sequence analysis of the 16S rRNA gene revealed that this organism is related to, but distinct from, several genera of lactic acid bacteria, principally several species of the genus Enterococcus. Phenotypic traits that serve to separate this organism from related genera include high levels of the cellular fatty acid C18 : 1omega9c and the production of ethanol along with lactic acid as fermentation products. Based on the collected phylogenetic and phenotypic evidence, it is proposed that the unknown organism represents a novel species in a new genus, Pilibacter termitis gen. nov., sp. nov. The type strain is TI-1T (= ATCC BAA-1030T = CCUG 49613T).