Pathogenic mechanism of chronic inflammation is associated with increased production of superoxide anion and hydrogen peroxide. In the neutralization process of that anions, superoxid dismutase (SOD), catalase (CAT), and glutation peroxidase (GPx) are key enzymes. Aim of study consists of establishing of some clinic-biological correlations in JRA chronic inflammation in childhood between clinical status and determination of lipoperoxidation products and antioxidative enzymes in the blood. METHODS Blood samples were obtained from 20 patients admitted in 2nd Clinic of Pediatrics, 4-6 months after onset of disease, diagnosed with JRA, oligoarticular form (6 cases), poliarticular form (9 cases) and systemic form (5 cases), as compared to 10 control subjects. SOD, CAT, GPx were measured comparing with malonildialdehyde (MDA), seric glutation (GSH) and usual inflammatory tests (ESR, fibrinogen, CRP). Determinations were repeated after 6 weeks of treatment. RESULTS In all our cases, level of antioxidant enzymes (CAT, GPx) was decreased at time of diagnosis, concomitant with increased MDA, SOD and inflammatory tests. In most of cases, after 6 weeks of correct anti-inflammatory treatment, levels of enzymatic antioxidant markers were still decreased, as compared to usual inflammatory tests that came back to normal. Persistent decreased antioxidant enzymatic activity was found in cases that need immunomodulatory activity (Methotrexat). CONCLUSIONS Determination of antioxidant enzymes level can be considered an evolution marker in JRA. More studies are necessary to find if antioxidant potential of blood can be used as following marker for immunosuppressive therapy.