Objective: Determine the incidence of dental caries and periodontal disease of the pit workers in Thong Nhat Coal Company, Quang Ninh. Subjects and methods: The cross-sectional studies on 403 workers are directly and indirect workers in Thong Nhat Coal Company - Cam Pha town, Quang Ninh from 12/2009 to 10/2010. Results: About the dental caries. Incidence of dental caries is 8.7 percent. Incidence of SMTR is 0.94. There is an average of 0.35 caries teeth/person, with 0.04 treatment teeth/person and 0.55 toothloss/person. Dental treatment need: 89 percent of teeth need to treatment. About the periodontal disease. Incidence of healthy periodontium is 9.7 percent, with periodontitis disease is 90.3 percent. Incidence of gingivitis is 16.4 percent. Incidence of the tartar is 62.5 percent. Periodontitis disease with low pockets is 9.4 percent. Periodontitis disease with deep pockets is 1.98 percent. Conclusions: Incidence of dental caries is 8.7 percent. Incidence of healthy periodontium is 9.7 percent, with periodontitis disease is 90.3 percent.