This study investigated the association between body fatness and periodontitis. The study population comprised 6,811 individuals who participated in the United States National Health and Nutrition Examination Survey (NHANES) 2009-2012 cycles. Body adiposity was evaluated using body mass index (BMI), and visceral adiposity was evaluated using waist circumference (WC). Periodontitis was defined using two methods: the Center for Disease Control and Prevention (CDC) and the American Academy of Periodontology (AAP) periodontitis case definition (CDC/AAP) and the Arbes et al. 2001 case definition (at least one site with ≥ 3 mm clinical attachment loss and ≥ 4 mm probing depth). The results showed that the prevalence of periodontitis was 41.8% according to the Arbes et al. 2001 definition and 45.7% according to the CDC/AAP definition. Based on Arbes et al. definition, those with BMI of 27-29.9 had a 34% increase in the odds of periodontitis (odds ratio (OR): 1.34, 95% confidence interval (CI): 1.08-1.66). Those who were obese (BMI ≥30) had a 47% increase in the odds of periodontitis (OR: 1.47, 95% CI: 1.22-1.76). High WC was associated with 63% higher odds of periodontal disease (OR: 1.63, 95% CI: 1.79-2.06). Based on the CDC/AAP case definition, neither high BMI nor WC were associated with periodontitis.