The aim is to determine the oxidative status of children with febrile neutropenia (FEN). Blood samples were collected to determine the total antioxidant capacity (TAC) and total oxidative status (TOS) of healthy children (once) and children with FEN after 0, 48, and 96 hours. Eighteen patients with FEN were evaluated. The baseline TAC level of patients was significantly higher than that of the controls (P<0.0001). The TAC levels of patients with FEN with and without antibiotic modification were higher than those of the controls (P=0.002 and 0.02, respectively). The TAC levels of the patients with FEN with antibiotic modification were lower than those of the patients without antibiotic modification (P=0.0224). The oxidative stress index (OSI), calculated TOS/TAS, value of the children with FEN was lower than that of the controls (P<0.0001). The OSI values of the patients with FEN with and without antibiotic modification were lower than those of the control group (P=0.001 and <0.0001, respectively). The TAC values of the patients with antibiotic modification were higher than those of the patients without antibiotic modification (P=0.02). In conclusion, the oxidative status of the children with FEN was affected, and it can give information about the follow-up of FEN.