Objectives : The purpose of the study is to find the association between obesity and periodontal disease by age in adults. Methods : The subjects were 5,728 adults in the first year of the Fifth National Health and Nutrition Examination Survey in 2010. The questionnaire included oral examinations, periodontal disease, and body mass index screenings. Chi-square test was performed to confirm the periodontal disease. Results : The impact of obesity and waist circumference on body mass index (BMI) showed high risk of periodontal diseases. The risk of periodontal disease according to BMI by age was closely related to obesity ranged form 35 to 59 yeard old. The increased waist circumference and those who were in 35 to 59 and over 60 years old had a significant association with the periodontal disease risk. Conclusions : Obesity and periodontal disease are closely related factors. Those aged from 35 to 59 are the high risk groups of potential obesity and periodontal disease. It is very important to control well-balanced nutrition and physical activity that can prevent the progression of periodontal disease.