Objectives: To determine the relationship between food insecurity and periodontitis among adults in the United States (US). Methods: Secondary analysis of the 2009-2014 National Health and Nutrition Examination Survey data. The sample included 6,108 US participants aged ? 30 years in a probability weighted sample. Periodontitis status was measured in full-month oral examinations at 6 sites per tooth for clinical attachment loss and periodontal probing depth. Food insecurity was assessed by the 18-item US Food Security Survey Module. Results: Controlling for covariates, multiple logistic regression showed that periodontitis was associated with low food security (adjusted odds ratio (aOR)=1.30, 95% CI: 1.08�1.57). Risk factors for periodontitis included HbA1c ? 7% (aOR=1.74, 95% CI: 1.26�2.40), seeking emergency dental care (aOR=1.36, 95% CI:1.19�1.55), smoking status, racial minorities, low income, and older age. Protective factors for periodontitis were annual dental visit (aOR=0.52, 95% CI: 0.43�0.64), health insurance (aOR=0.66, 95% CI: 0.54�0.80), female gender, and college education. Conclusions: Food insecurity was associated with a higher risk of periodontitis among US adults. Having enough food to eat is a basic human right and would improve well-being. Keywords: periodontal disease, United States, glycemic control, adult, food security, health surveys