According to the second National Epidemiological Survey on Dental Diseases conducted during 1995 and 1996, the prevalence of periodontal diseases in the Chinese population is higher than that found for dental caries. However, the number of dentists who provide periodontal treatment is low. Nevertheless, there has been considerable progress made in this research area during recent years. This article is a brief review of the research work on periodontal microbiology and host susceptibility to periodontal disease undertaken during the 1990s.