Objective To investigate the relationship between Toxoplasma gondii (T.gondii) infection and metabolic syndrome (MS).Methods A total of 20 577 patients who received serum test of anti-T.gondii IgG antibody in the National Health and Nutrition Examination Survey ( NHANES) of the United States from 2009 to 2014 were collected to analyze the clinical features of anti-T.gondii IgG antibody positive patients , and to compare metabolic related indicators in the antibody IgG positive and negative groups .The independent sample t-test, chi-square test, and logistic regression analysis were used to explore the risk factors of MS . Results A total of 2 746 participants were positive for the T.gondii antibody (13.34%), with a higher prevalence of male (14.44%vs 12.27%, χ2 ＝15.99, P＜0.01).Meanwhile, the prevalence of T.gondii increased with age and body mass index (BMI) (χ2 ＝979.98 and 50.85,respectively, both P＜0.01).Among the 2 191 patients with MS, 449 (20.49%) patients were positive for T.gondii.While 2 297 (12.49%) patients were anti-T.gondii positive in 18 386 non-MS patients.The difference was statistically significant (χ2 ＝78.504, P＜0.01).Age (t＝-37.37), BMI (t＝-4.28), glycosylated hemoglobin (t＝-11.81), fasting blood glucose (t＝-9.38), triacylglycerol (t＝-6.32), cholesterol (t＝-7.16), serum uric acid (t＝-5.25) and serum creatinine (t＝-7.69) in the seropositive group were all higher than those in the seronegative group (all P＜0.01).After adjusting for age and gender , the prevalence of T.gondii was an independent risk factor for MS (odds ratio [OR]＝1.147,P＝0.023).Conclusions BMI, blood lipids, blood uric acid and blood glucose are significantly increased in patients with T.gondii infection.T.gondii infection is an independent risk factor for MS.