Recent research has raised the possibility that electroconvulsive therapy (ECT) results in a persistent elevation of seizure threshold among males. In this study, seizure threshold, quantified by the method of limits procedure, was assessed at the first and last treatments of 148 consecutive depressed patients. Patients with and without a prior history of ECT did not differ in seizure threshold at the first treatment, seizure duration at the first treatment or averaged across all treatments, or in the magnitude of the seizure threshold increase over the ECT course. No evidence was obtained that history of ECT was associated with alterations of seizure threshold or seizure duration.