Background and aims: We undertook this study to evaluate the relationship between PON1, SOD and metabolic syndrome (MetS) in pediatric patients undergoing peritoneal dialysis, hemodialysis and patients in early stages of CKD. Methods: We carried out an analytical cross-sectional study of 134 children 6-17 years old. We registered anthropometric variables, vital signs, basic biochemical parameters, intact PTH (iPTH), high sensitivity CRP (hs-CRP), paraoxonase-1; SOD; PON1/HDL-cholesterol and homocysteine. For statistical analyses we used t test, Mann Whitney U test, χ(2), Fisher exact test, linear or logistic regression models, using SPSS v.16.0. p values