Objectives: The purpose of this study was to evaluate the chewing ability, oral-health related quality of life and factors in periodontal disease patients. Methods: Subjects were 111 patients having peridontal disease in 10 dental clinics in Busan and Gyeongsangnamdo. Questionnaire survey was carried out from July to August 2010. Questionnaire consisted of demographic characteristics, oral health factors, chewing ability and quality of life. Data were analyzed by descriptive analysis, t-test, ANOVA, correlation analysis, and multiple regression analysis using SAS(Ver 9.2) set at p<0.05. Results: Chewing ability was 44.85±8.8, and their quality of life was 41.7±8.8. Low level of quality of life was closely related to those factors as education, missing of more than 5 posterior teeth, certain subjective periodontal symptoms including swollen gums, sore gums, drifting gums, bad breath and toothache. The effective factors to the quality of life was chewing ability, bad breath and toothache. Conclusions: Chewing ability and quality of life were closely related each other. To enhance the quality of life, chewing ability should be improved. Proper treatment and effective method of management should also be properly considered to prevent the subjective periodontal symptoms and to minimize tooth loss.