BACKGROUND Anxiety disorders are common in children and adolescents, and they can significantly impair quality of life. Genetic, neurobiological, neurochemical, and psychological factors are believed to play a role in the etiopathogenesis of anxiety disorders. Recent evidence suggests that the pathophysiology of anxiety disorders may be associated with oxidative stress. In this study, we investigated whether there are associations between children with anxiety disorders and total oxidant/antioxidant status. METHODS The experimental group consisted of 40 patients (children and adolescents) with anxiety disorders. An age- and gender-matched control group composed of 35 healthy subjects was also assessed. Venous blood samples were collected and total antioxidative status (TAS), total oxidative status (TOS), and the oxidative stress index (OSI) were determined. RESULTS Both the TOS and the OSI of the experimental group were significantly higher than those of the control group. There were no significant differences in TAS between the experimental and control groups. LIMITATIONS The main limitation of our study was the small sample size. CONCLUSIONS This study suggests that oxidative balance is impaired in children with anxiety disorders. Oxidative stress may play a role in the etiopathogenesis of anxiety disorders, and TOS may be a useful diagnostic tool in this context.