This scientific statement reviews the pivotal role of triglycerides in lipid metabolism and reaffirms that triglyceride is not directly atherogenic but represents an important biomarker of CVD risk because of its association with atherogenic remnant particles and apo CIII. Although some familial disorders of triglyceride metabolism are associated with increased risk for pancreatitis when fasting triglyceride level exceeds 1000 mg/dL, others are associated with increased atherosclerotic risk. Moreover, IR, obesity, and sedentary lifestyle can all lead to or aggravate metabolic syndrome risk factors, which should urgently prompt clinicians to focus first on improving the patient's lifestyle. Knowledge of the metabolic pathways of triglyceride-rich particles and the consequences of hypertriglyceridemia is crucial in understanding the characteristic lipid alterations in DM, lipodystrophic disorders including those seen with HIV, and chronic renal disease. Measurements of non-HDL-C, apo B, or both may be especially useful in those with prominent triglyceride/ HDL abnormalities in which LDL-C measurements may underestimate true atherosclerotic vascular risk. © 2011 American Heart Association, Inc.