Determine the difference between the National Cholesterol Education Program Adult Treatment Panel (ATPIII) definition of the diagnosis of metabolic syndrome (MS) in Mexican adolescents and that by the International Diabetes Federation (IDF). We conducted a cross-sectional study of 575 adolescents aged 14 to 16 years using the student's t test, chi square and Spearman correlation. The prevalence of MS was higher by ATPIII (18.6%) than by IDF (8.2%) (p