Obesity is a well-known risk factor for metabolic syndrome. Although the cause or causes of metabolic syndrome are debated, insulin resistance, dyslipidemia, and hypertension are increasingly recognized in children and adolescents, especially those who are overweight or obese. Although adoption of a healthy lifestyle early in life offers the best long-term solution, many children and adolescents are currently at risk for future cardiovascular disease. Although long-term outcome data are lacking, the dyslipidemic triad commonly seen in youth with metabolic syndrome (elevated triglycerides, low high-density lipoprotein, and small dense low-density lipoprotein) is likely to significantly contribute to future vascular disease. Surrogate markers (carotid intima-media thickness and flow-mediated vasodilatation) for the precursors of cardiovascular disease are increased in obese youth, consistent with early vascular damage. In this work, we review the features of metabolic syndrome in children and adolescents, including age- and gender-specific norms for lipid values. Diagnostic criteria and modifications of screening guidelines unique to youth are discussed. Although recommendations for lifestyle modification are suggested for all, many youth at high risk of future cardiovascular risk may need more aggressive medical interventions to improve insulin sensitivity, achieve a less atherogenic lipid profile, and lower blood pressure.