Abstract Introduction: The COVID-19 pandemic caused relatively high mortality in patients, especially in those with concomitant diseases (i.e., diabetes, hypertension, and chronic obstructive pulmonary disease (COPD)). In most of aforementioned comorbidities, the oxidative stress appears to be an important player in their pathogenesis. The direct cause of death in critically ill patients with COVID-19 is still far from being elucidated. In this regard oxidative stress is one of the topics that need to be investigated. Therefore, the present research study was carried out to explore the relationship between the oxidant/antioxidant system and COVID‐ 19 exacerbation. Materials and Methods: A total number of 60 children were involved in this study; they further equally divided into patient and control group. Blood Samples were collected from 30children confirmed diagnosed with COVID-19 infection and 30 healthy children volunteers as the control group. The patient group consisted of 22children with mild disease and 8 children severely ill patients. Results: COVID-19 patients with mild and severe disease have shown the signs ofanaemia, leucocytosis and thrombocytopenia than control group. Serum levels of total antioxidant capacity (TAC) and nitric oxide (NO) were measured. TAC levels were considerably lower in patients compared with healthy individuals (control group). An increasing trend was found in NO concentration as well as MDA levels in patient group. Conclusion: These findings suggest that COVID-19 patients may be susceptible to depleted total antioxidant capacity. Moreover, showing such variations in blood samples of infected individuals could be considered as a predictive marker of COVID-19 severity.