We compared the serum levels of antinucleosome antibodies (anti-NCS Abs) in thirty pediatric systemic lupus erythematosus (SLE) patients by using enzyme-linked immunosorbent assay (ELISA) to 29 adult SLE patients, 30 healthy controls, 21 juvenile idiopathic arthritis (JIA) and 23 Henoch-Schonlein purpura (HSP) patients as autoimmune disease controls. The mean anti-NCS Ab titer in the pediatric SLE patients was 1552.7+/-1842.2 U/ml, higher than those of adult SLE patients (194.3+/-402.7 U/ml), normal controls (9.5+/-5.7 U/ml) and disease controls (JIA: 7.7+/-4.0 U/ml, HSP: 5.7+/-4.4 U/ml) (p<0.05). The prevalence of both anti-NCS Ab (90%) and anti-ds DNA Ab (76.7%) in pediatric SLE patients were higher (p<0.05) than that of adult SLE patients (58.6% and 48.3%). A positive correlation was demonstrated between anti-NCS Ab and anti-dsDNA Ab as well as the SLEDAI scores in pediatric and adult patients (p<0.05). The inverse correlation of anti-NCS Ab levels with C3 was observed in both pediatric and adult SLE patients (pediatrics, r=-0.61, p=0.0003; adult, r=-0.44, p=0.02). Our data suggested that in pediatric SLE patients, anti-NCS Ab could be as good a marker for SLE diagnosis and disease activity assessment as in adult SLE patients.