Two Gram-stain-positive, moderately thermophilic, endospore-forming, rod-shaped, motile bacteria designated PDF4(T) and PDF10, were isolated from Camkoy hot spring in the provinces of Aydin, Turkey and were characterized in order to determine their phylogenetic position. 16S rRNA gene sequence analysis revealed that the two strains belonged to the genus Brevibacillus. Strain PDF4(T) showed highest 16S rRNA gene sequence similarity to strain PDF10 (99.5 %), Brevibacillus brevis DSM 30(T) (98.9 %), Brevibacillus parabrevis DSM 8376(T) (98.6 %) and Brevibacillus formosus DSM 9885(T) (98.5 %); similarities to other species of the genus Brevibacillus were less than 98.5 %. The predominant fatty acids of strain PDF4(T) were anteiso-C-15 : 0 (60.0 %) and iso-C-15 : 0 (22.3 %). The polar lipids of strain PDF4(T) consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, an unknown phospholipid, two unknown lipid, an unknown aminophospholipid and two unknown aminolipids. MK-7 was detected as a sole respiratory quinone, and the cell wall of strain PDF4(T) contained meso-diaminopimelic acid. The DNA G + C content of strain PDF4(T) was 51.7 mol%. DNA-DNA hybridization showed less than 60 % relatedness between strain PDF4(T) and type strains of the most closely related species given above. Based on these data, the two strains are considered to represent a novel species of the genus Brevibacillus, for which the name Brevibacillus gelatini sp. nov. is proposed. The type strain is PDF4T (=NCCB 100559(T) =DSM 100115(T)).