Background: Childhood overweight and obesity is a global health problem that continues to worsen in many low-and middle-income countries. Low-cost measurements for monitoring overweight and relative metabolic risk, such as neck circumference (NC), should be evaluated in different populations and age groups. Aim: To test associations of NC and BMI with cardiometabolic parameters in 5-8-year-old Brazilian children. Methods: This cross-sectional study carried out from 2004-2006 measured height, weight and NC by anthropometry, and estimated fat and fat-free mass by bioelectrical impedance. Cardiometabolic risk factors assessed were systolic and diastolic blood pressure, high-and low-density lipoprotein cholesterol, triglycerides, and homeostatic model assessment of insulin resistance (HOMA). Associations of NC and BMI with cardiometabolic risk factors were tested using multiple regression and precision-recall plot analysis. Results: Analyses included 371 children (52% female). NC associated positively with BMI, fat mass, and fat-free mass, and with systolic blood pressure and HOMA following adjustment for age in sex-stratified multiple regression models. However, the latter relationships largely disappeared following adjustment for BMI. Area under the curve for NC or BMI in association with systolic blood pressure or HOMA >90 th percentile was low in the pooled sample, indicating poor classifier performance.