In this study, the bacteria from molar dental plaque and scrapings of the tongue of 12 conventional Sprague-Dawley rats on a diet of Purina Rodent Laboratory Chow No. 5001 and tap water were identified at the species or genus level quantitated using anaerobic culture techniques and selected biochemical tests. These results were compared to the microbial composition of dental plaque and scrapings from dental and tongue sites, evaluated by similar cultural techniques, of 7 caries-free students on a low-sugar diet for 3 weeks. Similarities did exist between the human and oral microflora, which included the percentage of gram-positive cocci, gram-negative cocci, Streptococcus mutans, and Streptococcus sanguis recovered at the dental sires. Differences from the human included the percentage of Actinomyces species, coliforms, enterococci, and Veillonella species recovered from the dental sites. The results suggest that the oral microflora of Sprague-Dawley rats should be considered whe model is used for human oral disease studies.