Background Surgical correction of tetralogy of Fallot (TOF) is still one of the most frequently performed intervention in pediatric cardiac surgery. The occurrence of seizures after repair or palliation of congenital heart disease (CHD) is a marker for a central nervous system (CNS) injury and has been associated with adverse neurodevelopmental sequelae. The prognostic value of electroencephalogram (EEG) for outcome prediction is glowing in children with CHD undergoing open-heart surgery who are at risk for subsequent neurodevelopmental deficits. To our knowledge, this is the first study to detect the EEG changes in neurologically free TOF patients after surgical repair Results Our study included 68 TOF cases and 32 sex- and age-matched control group; they were 66.0% males and 34.0% females. The mean age of the studied children was 11.41 ± 4.23 years. There was statistically significant difference between TOF patients and control group as regards alpha power and Delta% in left occipital region and Alpha% in right occipital region, with dominant alpha waves in patients’ right occipital region. None of our patients had epileptic waves. The duration after operation showed negative correlation with Delta% at left occipital region and positive correlation with Alpha% in right occipital region (p = 0.002, p = 0.044 respectively). Conclusion TOF cases showed changes in EEG parameters chiefly dominant alpha power and Delta% in left occipital region and dominant Alpha% in right occipital region. Duration after surgery correlated negatively with Delta% at left occipital region, and positively with Alpha% in the right occipital region. Subsequent assessment is recommended to study long-term hazards of these varied dominance of EEG waves in our patients, e.g., evaluation of the cognitive functions.