The aims of this study were to compare threshold and suprathreshold ictal electroencephalograms (EEGs) in right unilateral (RUL) ultrabrief (UB) electroconvulsive therapy (ECT) and to identify the differences between these EEGs. This study is a retrospective review of 125 pairs EEGs from titration and subsequent sessions across a 2-year period. All EEGs were independently rated for by 2 assessors using a scale based on qualities of an EEG used to guide ECT treatment dose adequacy, for example, midictal amplitude, regularity, interhemispheric coherence, seizure end point, and postictal suppression. The scores of threshold and suprathreshold EEGs were compared within and between groups based on 2 ECT types, that is, RUL UB ECT and RUL brief pulse (BP) ECT. Paired t tests showed a statistically significant difference in between threshold and suprathreshold EEG scores in RUL UB ECT. There were no statistically significant differences between corresponding scores for RUL UB ECT and RUL BP ECT threshold and suprathreshold EEGs. There is a significant difference between the quality of threshold and suprathreshold EEGs in RUL UB ECT when measured with an EEG rating scale. Visual rating of ictal EEGs is as reliable in discriminating between threshold and suprathreshold seizure in RUL UB ECT as it is in RUL BP ECT.