Objective: To establish, among the cut-off values for the homeostatic model assessment for insulin resistance index (HOMA-IR) cited in the literature, the best in identifying metabolic syndrome (MS) in obese and overweight children., Methods: A total of 106 pre-pubertal children were studied. The definition of MS was adapted from that of the International Diabetes Federation. For each cut-off values for HOMA-IR, it was estimated sensibility and specificity for MS. A receiver operating characteristic (ROC) curve was generated using these values., Results: The study included 106 obese (37 girls and 69 boys) and 34 overweight (19 girls and 15 boys) children aged 6,5 +/- 2,3 years. The accuracy of the ROC curve was 72%, and the best cut-off value for HOMAIR was 2,5, with sensitivity of 61% and specificity of 74%., Conclusions: HOMA-IR may be useful to detect MS and the cut-off 2,5 seems to be the best in obese and overweight pre-pubertal children.