The aim of this study was to establish the antioxidant status and oxidative stress in adult patients with chronic idiopathic thrombocytopenic purpura (ITP). Eighty-four patients diagnosed with chronic ITP were studied. Fifty-eight age-matched healthy subjects were selected as controls. Serum nitrogen monoxide ( NO), oxidized glutathione (GSSG), malondialdehyde (MDA), total antioxidant status (TAS), total oxidant status (TOS), superoxide dismutase(SOD), hydrogen peroxide enzyme (CAT), glutathione peroxidase (GSH-Px), glutathione (GSH) were evaluated by enzyme-linked immunosorbent assay (ELISA). It was found that serum SOD, CAT, GSH-Px, GSH, TAS levels were significantly lower in patients with chronic ITP than controls (all P < 0.05), while serum NO, GSSG, MDA, TOS values were significantly higher (P < 0.05). The number of platelet showed a negative correlation with NO, GSSG, MDA, TOS, respectively,while platelet number showed a positive correlation with SOD, CAT, GSH-Px, GSH, TAS. These findings suggested that oxidants were increased and antioxidants were decreased in patients with chronic ITP, these may be prominent factors in destructing the platelet membrane. The scavenging of oxygen radical provides a theoretical basis for the treatment of ITP patients.