This study tested the hypothesis that the "hypertriglyceridemic waist" phenotype (waist girth >90 cm [35.4 inches] in men and >85 cm [33.5 inches] in women, along with a plasma triglyceride concentration of >or=2.0 mmol/L [177 mg/dl]) as a covariate of metabolic syndrome features (hyperinsulinemia, hyperapolipoprotein B, and small low-density lipoprotein particles), is predictive of premature coronary artery disease (CAD) among patients with glucose intolerance or type 2 diabetes. Glucose intolerance and type 2 diabetes were assessed after an oral glucose tolerance test among 1,190 men and women using the American Diabetes Association criteria. Glycemic control was evaluated using hemoglobin A1c levels. CAD was considered present on the basis of a clinical history of retrosternal pains on exertion, electrophysiologically and clinically documented myocardial infarction, or angiographic evidence of coronary lesions. More than 53% of men (n = 103) with a waist circumference >or=90 cm (35.4 inches) and nearly 80% of women (n = 122) with a waist circumference >or=85 cm (33.5 in.) with triglyceride levels >or=2 mmol/L (177 mg/dl) were diagnosed with glucose intolerance or type 2 diabetes. Survival models revealed that those with glucose intolerance or type 2 diabetes with the "hypertriglyceridemic waist" phenotype experienced their first CAD symptoms 5 years earlier than those without this phenotype. This elevated and earlier risk of CAD was statistically significant (hazard ratio 2.0, 95% confidence interval 1.2 to 3.7, p = 0.02). In conclusion, the "hypertriglyceridemic waist" phenotype, an inexpensive and simple tool identifying subjects with metabolic syndrome features, is a significant marker of CAD manifestations occurring at an earlier age in those with glucose intolerance or type 2 diabetes.