OBJECTIVES To quantify prevalence of metabolic syndrome in U.S. ethnic groups and determine ethnic differences in health habits among sufferers. METHODS Data were obtained from the 2008 U.S. National Health and Wellness Survey (NHWS), a national, patient-reported, Internet-based study of health care attitudes, behaviors, health status, and outcomes of adults aged 18+. Metabolic syndrome was defined as experiencing at least three of the following: type 2 diabetes, high cholesterol, hypertension, BMI ≥ 30. Smoking, regular exercise (16+ times/month), visiting a physician in the past six months, and insurance status were assessed. Frequency weights based on age, race and gender were used to calculate prevalence estimates. Logistic regression was used to determined effects of ethnicity on metabolic syndrome and health habits among sufferers while adjusting for other demographics. Analyses were limited to self-identified white (reference group), black, Hispanic and Asian respondents. RESULTS Of the 61,016 respondents, 9.0% (projected 16.7M; 7.8%) experienced metabolic syndrome. Prevalence varied across ethnic groups: White=12.8M, 8.4%; Black=19.5M, 7.9%; Hispanic=1.6M, 5.8%; Asian=0.3M, 3.2%). Adjusting for other demographics, blacks were more likely (OR=1.35, p<0.01), Asians less likely (OR=0.58, p<0.01), and Hispanics equally as likely to have metabolic syndrome as whites. There were significant (p<0.05) ethnic differences in selected health habits among sufferers after adjusting for other demographics. Specifically, Hispanics were 0.69 times as likely to be current smokers and 0.69 times as likely to visit a primary care physician as whites, and blacks were 0.64 times as likely to have health insurance as whites. CONCLUSIONS Complex conditions such as metabolic syndrome present new challenges in ethnic health and healthcare research due to variations in the prevalence and risk factors by ethnic groups. Among metabolic syndrome sufferers, ethnic disparities in health habits, physician visits, and insurance status may lead to differential outcomes by ethnic group.