Background/objectives: Extremes of birthweight (BW) have been associated with increased rates of metabolic risks. The objective was to study the prevalence of metabolic risks markers among obese and overweight (OW) subjects according to BW. Subjects/methods: A cross-sectional study was performed in a cohort of 1002 patients (2 - 18 years, 40.6 % male) evaluated for OW or obese subjects in two private clinics. Anthropometrics, fasting lipids, glycemia, and insulin were obtained. Results: Of the subjects, 76.1 % were born appropriate for gestational age (AGA), 10.9 % small for gestational age (SGA), and 13 % large for gestational age (LGA). Children born LGA presented a more severe degree of obesity compared with those born AGA and SGA (p < 0.0001). No differences in glycemia, insulin, and lipid levels were detected among the groups. Abnormal glucose was found in 37 subjects: one with type 2 diabetes mellitus (from the previously glucoseintolerant subjects), 10 with glucose intolerance, and 27 with impaired fasting glucose. According to Boney criteria, 6.6 % of the patients (6 - 18 years old) exhibited metabolic syndrome (MS) (69.4 % AGA, 12.9 % SGA, and 17.7 % LGA). Conclusions: Being born LGA represents a higher risk of severe obesity. At this age, the most frequent component of MS was an abnormal lipid profi le with low high-density lipoprotein and high triglycerides. Finally, the most frequent fi nding associated with abnormalities of glucose tolerance was a family history of diabetes. Thus, BW, lipid profi le, and family history are mandatory when these patients are evaluated.