This article investigated the possible neurotoxic effect of sulfite in normal and sulfite oxidase (SOX) deficients rats by evaluating EEG spectral analysis. Rats were divided into four groups: control (C), sulfite treated (25 mg/kg) (ST), SOX deficient (SD), and sulfite treated SOX deficient (STSD) groups. The qEEG spectral analyses of two spectral parameters including power and relative power were performed. The mean power of SD group was found to be increased compared to the all other groups and returned to control levels after sulfite administration. The power of the four frequency bands (delta, theta, alpha, beta) of the SD group corresponds to the mean power. EEG relative power increased in the delta band with concomitant decreases in power measured in the alpha frequency range. It was concluded that exogenous administration of sulfite affected the brain electrical activity in SOX deficiency, and improved neuroprotection.