Previous studies have demonstrated that demographic characteristics of subject populations influence both the incidence of periodontal diseases and various aspects of host responses to periodontal bacteria. In this study we analyzed the components of the subgingival microflora from individuals with adult periodontitis, early onset periodontitis, gingivitis, and periodontal health as a function of gender and race (black and white). Clinical categories were analyzed individually so that there were no differences in the clinical characteristics of the sampled sites. No significant differences were noted in the subgingival microflora between males and females. When either the first two bacterial samples from each subject or all bacterial samples taken from each subject were included in the analysis, it was found that Porphyromonas gingivalis was more significantly associated with black subjects in the adult periodontitis group. When all samples were considered in the analysis, it was found that Peptostreptococcus anaerobius was associated with black subjects in the adult periodontitis group, while Fusobacterium nucleatum was associated with white subjects in both the adult periodontitis and early onset periodontitis groups. Thus a limited number of important bacterial components of the subgingival microflora are influenced by the race and diagnosis of the subject group.