Objective To investigate the prevalence and predictors of postictal confusion (PIC) in patients who received electroconvulsive therapy (ECT). Methods We conducted chart reviews for 79 patients who were receiving inpatient ECT. Subjects with PIC were identified. PIC was defined by confusion, disorientation, motor restlessness, purposeless movement, and nonresponse to verbal commands following ECT within an hour, intravenous benzodiazepine was necessary to manage disturbed behavior. Multivariable logistic regression analysis was used to examine the association of PIC with demographic and clinical variables. Results Prevalence of PIC was 36.7%. In 912 ECT sessions, the occurrence of PIC was 86 times. Patients with PIC (n = 29) had significant higher body mass index (BMI) (27 ± 6.6 kg/m 2 vs 24.1 ± 5.2 kg/m 2 , t = −2.22, df = 77, p = 0.029) than patients without PIC (n = 50). PIC associated with BMI (Pearson correlation = 0.25, p = 0.029). BMI was significant predictor of PIC after adjusting for other covariates (odds ratio = 0.91, 95% CI= 0.83–0.99, p < 0.035). Conclusion PIC was not uncommon in patients receiving ECT. BMI was an independent predictor of PIC. Psychiatrists should be aware of the risks of PIC in patients with high BMI receiving ECT.