Background : Electroconvulsive therapy(ECT) still remains a place in modern psychiatric practice. The anesthetic agent for ECT should provide smooth and rapid induction, rapid recovery and attenuation of the physiologic effects of ECT as well as minimal antagonistic effects on seizure activity. We performed a study to assess the comparative effects of propofol and thiopental sodium on seizure activity, hemodynamic stability, and recovery after ECT. Methods : Ten patients scheduled for maintenance ECT participated in this prospective, randomized, crossover study. The induction dose was 1.5 mg·kg 1 of propofol and 3 mg·kg 1 of thiopental sodium. The lengths of motor and EEG seizure were measured after each electric stimuli. Mean arterial pressure, heart rate and recovery time were also compared between two groups. Results : Both propofol and thiopental sodium were associated with mean motor and EEG seizure durations above thirty seconds. However, the improved hemodynamic stability associated with propofol and recovery time of propofol(8.1 2.8 min) was shorter than thiopental sodium(13.0 9.3 min). Conclusions : Compared with thiopental sodium, the use of propofol was associated with a clinically insignificant decrease in seizure duration and improved hemodynamic stability, recovery time. We conclude that propofol may be a useful alternative to thiopental sodium for ECT therapy. (Korean J Anesthesiol 1998; 34: 932∼936)