Background: Electrical status epilepticus in sleep (ESES) is an epileptic syndrome specific to childhood and has a broad clinical spectrum that included seizures, behavioral/cognitive impairments, and motor neurological symptoms. Antioxidants are seen as promising neuroprotective strategies for the epileptic state by combating the harmful effects of excessive oxidant formation in mitochondria. Objective: This study aims to evaluate the thiol-disulfide balance and to determine whether it can be used in the clinical and electrophysiological follow-up of patients with ESES, especially in addition to the electroencephalography (EEG) examination. Methods: The study included 30 patients, aged 2-18 years and diagnosed with ESES in the Pediatric Neurology Clinic of the Training and Research Hospital and a control group of 30 healthy children. Total thiol, native thiol, disulfide, and ischemia-modified albumin (IMA) levels were measured, and disulfide-thiol ratios were calculated for both groups. Results: Native thiol and total thiol levels were significantly lower and IMA level and disulfide-native thiol percentage ratio were significantly higher in the ESES patient group than in the control group. Conclusion: Serum thiol-disulfide homeostasis is an accurate marker of oxidative stress in ESES, and standard and automated measures of thiol-disulfide balance as an indicator of oxidative stress showed a shift toward oxidation in ESES patients in this study. The negative correlation between spike-wave index (SWI) and thiol levels, and serum thiol-disulfide levels suggest that they can be used as biomarkers for follow-up of patients with ESES in addition to EEG. IMA can also be used for long-term response to monitoring purposes at ESES.