A bacterial strain, designated KUFDS01T, isolated from human saliva was characterized using a polyphasic taxonomic approach that included analysis of physiological and biochemical features, cellular fatty acid profiles and phylogenetic position based on 16S rRNA gene sequence analysis. Cells of the strain were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-stain-negative rods. Growth of the strain was inhibited on medium containing 20% bile. The 16S rRNA gene sequence analysis showed that the strain was a member of the genus Porphyromonas. Strain KUFDS01T was closely related to Porphyromonas catoniae JCM 13863T (96.6% sequence similarity). An hsp60 gene sequence analysis indicated that strain KUFDS01T was different from P. catoniae JCM 13863T, with a sequence similarity value of 87.8%. The major cellular fatty acids of strain KUFDS01T were C16 : 0, iso-C15 : 0, anteiso-C15 : 0, C18 : 2ω6, 9c and C18 : 1ω9c. The DNA G+C content of strain KUFDS01T was 57.7 ± 0.66 mol%. On the basis of these data, strain KUFDS01T represents a novel species of the genus Porphyromonas, for which the name Porphyromonas pasteri sp. nov. is proposed. The type strain of P. pasteri is KUFDS01T ( = JCM 30531T = CCUG 66735T).