Objective: To establish the importance of evaluating ultrasensitive C-reactive protein (us-CRP) in a pediatric group with obesity as the main biomarker, detecting, as early as possible, cardiometabolic complications. Methods: This is a control-case, cross-sectional study involving the biochemical and anthropometric evaluation of 342 children and adolescents participating in the Preventive Medicine Service, in Aracaju, Sergipe, Brazil. When evaluated anthropometrically, it was observed that, in 235 of the cases, the body mass index (BMI) above the 97th percentile or the Z-score greater than +2 allowed their classification as obese. The control group consisted of 107 non-obese individuals. The sample was divided into three age groups according to the International Diabetes Federation (FID): 6-10 years, 10-16 years and >16 years, representing 45%, 39% and 14% of the sample population, respectively. Results: The CRP-us showed an average value of 2.36 +- 1.28 mg/dL in the obese group, while in the control group, the result found was 0.01 +- 0.1 mg/dL. There was a significant correlation between the increase in CRP levels in the obese group and other biochemical and anthropometric findings in the same group, such as: reduced HDL, elevated triglycerides, higher BMI, and increased abdominal circumference (AC). Homocysteine, in turn, proved to be a biomarker with little specificity in the sample in question. Conclusion: The ultra-sensitive C-reactive protein, already fundamentally correlated with increased cardiovascular risk in adults, demonstrates to be a validated biomarker, showing high sensitivity even in pediatric obese populations.