Background: The prevalence of the metabolic syndrome (MS) is growing. The Adult Treatment Panel (ATP) III provided a uniform definition of MS but no information on its predictive ability. Methods: We tested the ability of MS and its components to predict angiographic coronary artery disease (CAD) and incident death/myocardial infarction (D/MI) over 2.8 ± 2.3 years in a large cohort of patients undergoing angiography. ATP-III criteria were used for fasting glucose (FG), triglyceride (TG), high-density lipoprotein cholesterol (HDL), and blood pressure (BP); body mass index (BMI) >27 kg/m<sup>2</sup> was used as a surrogate for waist circumference. Results: 3,128 subjects were studied; 65% had advanced CAD (≧70% stenosis), and 35%, no CAD. MS was present in 64% (high FG 40%; high TG 52%; low HDL 71%; high BP 76%; high BMI 58%). Presence of CAD was predicted by MS [adjusted odds ratio (OR) = 1.30, 95% CI 1.10–1.55, p = 0.003] and, individually, by high FG (OR = 1.90, CI 1.63–2.23) and low HDL (OR = 1.38, CI 1.18–1.62). In multivariable modeling, CAD was predicted by high FG (OR = 1.80, CI 1.51–2.16) and low HDL (OR = 1.57, CI 1.31–1.89) as well as by age, gender, family history, smoking, and LDL cholesterol (all p < 0.001). For secondary risk of incident D/MI, only high FG of MS features was predictive (adjusted hazard ratio 1.46, CI 1.17–1.82, p = 0.001), and this risk was carried by diabetes (adjusted hazard ratio 1.71, p < 0.001); other predictors were age, heart failure, revascularization strategy, renal insufficiency, prior MI, and number of diseased vessels. Conclusion: MS has primary predictive ability for CAD, carried primarily by high FG and low HDL. Secondary predictive ability of MS features for clinical outcomes, in the setting of established CAD, is carried by diabetes alone. Dysglycemia deserves specific attention as a target for prevention and treatment.