PURPOSE: A decrease in posterior occlusal support is considered to increase the load on remaining teeth and thus accelerate tooth loss. Therefore, a follow-up study was carried out to perform a longitudinal analysis of the association between the posterior occlusal support region and tooth loss. METHODS: The participants of the study were 806 Suita Study participants who underwent physical health checkups both at baseline and at follow-up. The participants were classified into three groups by posterior occlusal support area (POSA) using the Eichner Index at baseline: Perfect POSA group, Eichner A; Decreased POSA group, Eichner B1-3; and Lost POSA group, Eichner B4 and Eichner C1-2. Participants were also classified into two groups according to whether they had tooth loss during the follow-up period. Tooth loss risk factors were investigated through the construction of logistic regression models with tooth loss as the dependent variable and posterior occlusal support, sex, age, periodontal disease, stimulated salivary flow rate, smoking habit, drinking habit, denture wearing, utilization of dental services, brushing habits, diabetes mellitus, osteoporosis and number of years of follow-up as independent variables. RESULTS: In the results of the logistic regression model, the adjusted odds ratio (95%CI) for tooth loss with the Perfect POSA group as the reference was 3.19 (1.98-5.14) for the Decreased POSA group and 4.57 (1.97-10.62) for the Lost POSA group. CONCLUSIONS: This study showed that decreased POSA accelerated tooth loss in the general urban population.