Background and aim: Sepsis is a leading cause of morbidity and mortality in critically ill children worldwide. Studies show that pediatric septic shock mortality is higher when anemia is present. Increased oxidative stress, indicated by elevated F2-isoprostanes (F2-isoPs), is common in critically ill patients, but in anemia, antioxidant defenses are impaired, as shown by reduced glutathione peroxidase (GPx) levels. Despite these findings, only a few studies have specifically examined the role of anemia in pediatric septic shock through the lens of oxidative stress. This study aims to investigate the role of oxidative stress in children with septic shock, comparing those with and without anemia. Methods: A cohort of 30 children with septic shock, aged six months to 18 years, was monitored for three days. Hemoglobin levels, GPx, and F2-isoPs levels were measured daily. Statistical analysis was performed to compare the anemia and non-anemia groups. Results: Of all the samples, 15 children were anemic and 15 were not. Overall mortality was 70%. Hemoglobin and GPx level on the third day measurement showed a significant difference between survivors and non-survivors. The levels of GPx as a mortality predictor showed a sensitivity of 59% and a specificity of 60%, while GPx/ F2-isoPs as a mortality predictor showed sensitivity of 59% and specificity of 62%. Conclusions: Anemia affects mortality in children with septic shock by decreasing antioxidant defense. © Mattioli 1885.