Introduction: In recent years, the prevalence of metabolic syndrome (MetS) in various countries shows a fast, rising trend, that can be caused by lifestyle changes, including changes in diet. Despite the possible association between dietary fats and the MetS receiving attention, limited studies have determined the association between oils (hydrogenated and non-hydrogenated) and the MetS. The aim of this study was to investigate the association between hydrogenated and non-hydrogenated vegetable oils and the metabolic syndrome among Tehranian adults. Materials and Methods: This cross sectional study was conducted within the framework of Tehran Lipid and Glucose Study between 2005 and 2008, on 2457 adults, aged 19-84 years. Intakes of vegetable oils were assessed using a validated semi quantitative food-frequency questionnaire. Anthropometrics, blood pressure, and biochemical measurements were assessed. The metabolic syndrome based on the definition of the Iranian National Committee of Obesity. Results: Mean age and BMI of participants was 39.3 years and 25.7 kg/m2, respectively. Median daily intakes of hydrogenated vegetable oils (HVOs) were 9.6 g/d and those of non-hydrogenated vegetable oils (NHVOs) were 6.0 g/d. Higher intakes of HVOs and NHVOs were associated with higher intakes of total energy intake, total fat, saturated fatty acids, cholesterol, fiber, vegetables, legumes, meat, poultry and fish and lower intake of carbohydrates. After controlling for potential confounders, compared to the lowest tertile of HVOs, odds ratio for metabolic syndrome in the highest tertile was 2.54 (95% CI: 1.53-4.23). NHVOs were not associated with the prevalence of metabolic syndrome. Conclusions: HVOs intake was found to be positively associated with metabolic syndrome among Tehranian adults.