In this study, alpha-linolenic acid (ALA) intake was found to be inversely associated with the metabolic syndrome (MetS.) This cross-sectional study investigating the association of the intakes of omega-3 (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and omega-6 polyunsaturated fatty acids (PUFAs) with metabolic syndrome (MetS) in adults, was conducted in a random sample of participants (n = 2451, 19-84 y old) in the Tehran Lipid Glucose Study. Dietary intake was assessed using a validated semiquantitative food-frequency questionnaire. Anthropometric characteristics, blood pressure, and fasting plasma concentrations of glucose and lipids were measured. MetS was defined according to the Adult Treatment Panel III guidelines. Researchers found ALA and omega-6 intakes were inversely associated with the MetS, but that dietary ratio of omega-6 to omega-3 was not. Subjects with at least the median ALA intake (1084 mg/d) had a lower prevalence of the MetS, irrespective of omega-6 intake. Results suggest that ALA intake may be inversely associated with the MetS in adults.