EEG is important in monitoring neonates with hypoxic-ischemic encephalopathy (HIE) during hypothermia therapy (HT). Although EEG is used to evaluate the severity of HIE and predict outcome, HT itself may affect EEG parameters. The goal of this study is to evaluate whether core body temperature (CBT) during the rewarming phase of HT in neonates with HIE changes quantified EEG parameters. Quantified EEG parameters were reviewed in 10 neonates with HIE treated with HT. Total power, 90% spectral edge frequency, the mean and lower border of amplitude-integrated EEG (aEEG), and approximate entropy of the aEEG were calculated from 10-minute samples centered on CBT measurements. Patients were classified by clinical HIE severity and length of stay. Two-way analysis of variance was used to test interactions among CBT and EEG data. CBT had no significant effects on the quantified EEG parameters. The aEEG-average and lower border amplitudes were significantly lower in severe HIE. The aEEG-average was significantly more orderly in patients with longer length of stay, regardless of CBT. HIE severity and length of stay but not CBT affect quantified EEG. Findings suggest quantified EEG is reliable during HT. In addition, EEG may aid in predicting short-term outcome of neonates with HIE.