As the prevalence of childhood obesity increases, its health implications are becoming evident to pediatricians around the country. Most striking is the unprecedented epidemic of abnormalities in glucose metabolism, with the diagnosis of type 2 diabetes (T2DM) outnumbering the diagnosis of type 1 diabetes mellitus in many Pediatric Endocrine Clinics. Furthermore, the "Metabolic Syndrome" may be present in as many as 30% of obese adolescents and is manifested by the typical coexistence of central obesity, dyslipidemia, hypertension and impaired glucose tolerance or pre-diabetes. For the past ten years, our laboratory has focused on the metabolic consequences of obesity in youth. We have observed that alterations in the partitioning of fat in both muscle and abdominal tissues in these individuals is closely linked to insulin resistance and abnormalities in glucose homeostasis. Furthermore, we have been able to examine metabolic factors that predict the development of T2DM in obese children. We are currently examining the effect of impaired glucose tolerance on the vascular health of obese youth and have found that subtle shifts in glucose metabolism are associated with microalbuminuria, a surrogate marker of endothelial function and premature cardiovascular mortality.