['Muscle symptoms have been associated with statin use, but the relationship of statin-associated muscle symptoms with metabolic syndrome (MS) has not been reported previously.', 'To evaluate the relationships between MS and its individual components with statin-associated muscle symptoms.', 'Data were analyzed from the Understanding Statin Use in America and Gaps in Education (USAGE) study. Modified criteria to define the MS were used based on self-reported survey data.', 'Among USAGE subjects, the MS was present in 1364 of 3992 men (34.2%) and in 1716 women of 6149 women (27.9%). Subjects with the MS were 19% more likely (P\xa0=\xa0.0002) to report new or worsening muscle symptoms while on a statin. Three MS criteria-increased BMI, elevated triglycerides (TG), and low high-density lipoprotein cholesterol (HDL-C)-were associated with increased odds of muscle symptoms, by 18%, 32%, and 28%, respectively (all P\xa0<\xa0.001). The presence of MS also predicted increased odds of having discontinued a statin due to muscle symptoms (13% higher, P\xa0=\xa0.043). Among criteria for the MS, elevated TG (38% higher odds, P\xa0<\xa0.0001) and low HDL-C (37% higher odds, P\xa0=\xa0.0003) were positively associated with statin discontinuation, whereas hypertension (13% lower odds, P\xa0=\xa0.019) and diabetes mellitus (12% lower odds, P\xa0=\xa0.036) were inversely associated.'] Is metabolic syndrome associated with muscle symptoms among statin users?