The objective of this study was to compare the prevalence of overweight and obesity in children from northwest of Mexico based on BMI/age and three criteria of growth reference standards. Six hundred and four children, 6 to 10 years of age, from 17 municipalities of the state of Sonora were measured for weight and height and age established from birth certificate school records. The prevalence of overweight and obesity was determined by the new version of the US Centers for Disease Control and Prevention (CDC/NCHS), the International Obesity Task Force (IOTF) and the values proposed by The World Health Organization (WHO) that was utilized in the National Nutrition Survey of 1999 in Mexico (ENN). Using the WHO reference, prevalence of overweight and obesity was 39%. This was higher than the CDC/NCHS (20%) and IOTF (17%) references, respectively. Prevalence of overweight and obesity by CDC/NCHS and IOTF criteria, showed the best agreement (Kappa >80); this was not the case when prevalence from CDC/NCHS and IOTF were compared to the WHO criteria (Kappa <40). For overweight and obesity frequencies, no sex or urban-rural differences were observed (p>0.05). In conclusion, the use of these 3 reference values systems using BMI/ age did not show the same prevalence estimates of overweight and obesity. The use of the WHO method can overestimate the prevalence of obesity in children, therefore the use of these 3 references should be considered for future comparisons.