We sought to examine the association of food security and metabolic syndrome in a representative sample of U.S. adults and adolescents. We hypothesized that compared with those in food-secure households, adolescents and adults living in food-insecure households would have increased odds of (MetS).Data from the National Health and Nutrition Examination Surveys from 1999 to 2006 were combined and analyzed cross-sectionally. Logistic regression was used to compute odds ratios and 95% confidence intervals (95% CI) in the association of household food security (fully food secure, marginal, low, and very low food security) and MetS.Compared with those who were food secure, adults in households with marginal food security had 1.80-fold increased odds of MetS (95% CI, 1.30-2.49), and those with very low food security had a 1.65-fold increased odds of MetS (95% CI 1.12-2.42). There was no association with low food security. The association of marginal household food security and MetS was not significant in adolescents. In adults and adolescents, very low was food security not associated with increased odds of MetS compared with those who were food secure.Members of households with marginal and very low food security are at increased risk of MetS. A mechanism may be that foods that are inexpensive and easily accessible tend to be energy dense and nutrient poor.