Purpose : This epidemiological research was conducted to investigate the relationship between the groups of TMD and the behavioral, psychological, and physical symptoms through RDC/TMD. Subjects and Methods : The subjects of this research were the 286 patients who had visited Seoul National University Bundang Hospital; their common chief complaint was temporomandibular discomfort. The mean age of the patients was 32.9 from 11 to 85, and the number of men and women was 67 and 219, respectively. The patients were examined through clinical and radiological methods and diagnosed by 1 investigator. They were divided into 3 groups: myogenous group (group 1), arthrogenous group (group 2), and combined group (group 3). The behavioral, psychological, and physical symptoms were evaluated through questionnaires on RDC/TMD. Specific items were selected to calculate the graded chronic pain (characteristic pain intensity, disability points), jaw disability, depression, and non-specific physical symptoms (pain items included/excluded) in the questionnaire. One-way ANOVA, Kruskal-Wallis test, and chi-square test were applied as statistical methods. Results : As a result of classifying temporomandibular disorder in this study, the patients were distributed as follows: 9.1% of group 1, 79.7% of group 2, and 11.2% of group 3. In the analysis of graded chronic pain (characteristic pain intensity, disability points), jaw disability, and non-specific physical symptoms (pain items included/excluded), group 3 had the highest score, and the difference was significant (p<0.001). Moreover, the depression score of group 3 was significantly higher than groups 1 and 2 (p<0.05). Note that that the second order of jaw disability score was group 2, on the other hand, those of the other groups were group 1. Conclusion : Myofascial pain could be assumed to be related closely to the behavioral, psychological, and physical symptoms except jaw disability compared to joint pain through RDC/TMD.