ABSTRACTObjective:To evaluate the frequency of obesity and cardiometabolic risk in schoolchildren under ten years old.Methods:This is a cross-sectional study with schoolchildren (n=639) aged five to ten years in a municipally of southern of Brazil. The cardiometabolic risk was calculated from values of body mass index (BMI), waist circumference (WC), diastolic (DBP) and systolic blood pressure (SBP), blood glucose levels, triglycerides and total cholesterol (TC). Odds ratio (OR), Spearman correlation and principal component analysis (PCA) were analyzed.Results:Independent of sex, elevated WC and BMI were related to higher values of SBP, DBP, and TC in schoolchildren. The frequency of cardiometabolic risk was 6.0% in girls and 9.9% in boys. Schoolchildren with elevated values of SBP, triglycerides and TC presented high OR for cardiometabolic risk. PCA indicated that schoolchildren with high WC (p>80) presented more frequently altered glucose levels, triglycerides, and TC.Conclusions:Obesity, especially when associated with elevated WC, is related to metabolic dysfunctions and cardiometabolic risk in schoolchildren under ten years of age. These findings indicate the urgency of stablishing metabolic risk for this age group, enabling early diagnosis and adequate treatment, to prevent the development of diabetes and cardiovascular dysfunction throughout life.