Abstract Physiological parameters such as blood pressure (BP) and heart rate (HR) reflect autonomic response after seizure and may correlate with therapeutic efficacy in electroconvulsive therapy (ECT). However, the literature has been inconclusive with regard to the relationship between the effectiveness of ECT and physiological markers without atropine. In a consecutive sample of 24 patients with a drug-resistant major depressive episode who underwent modified sine or pulse wave ECT without atropine, the correlation was examined between BP and HR before, and 2 min after electrical stimulation and therapeutic efficacy on depressive symptoms. When mode of stimulation (sine wave or pulse wave) and baseline Hamilton Rating Scale for Depression (HRSD) were controlled for, postictal diastolic BP, systolic BP, HR and rate pressure product (RPP) were all found to be significant predictors of post-treatment HRSD. When these predictors were entered into stepwise regression, both postictal systolic BP and HR remained as significant predictors. The higher these postical physiological parameters, the more effective the course of ECT. It may be useful to examine such sensitive physiological parameters as BP, HR or RPP to determine effective or non-effective electrical seizure.