The purposes of this study were to obtain a detailed description of the clinical features of pseudoepileptic (PE) seizures, to try to reproduce these events in the laboratory during a single recording, and to establish a framework useful to the clinician for evaluating patients whose behavior suggests physiological seizures, but about which doubt remains. We analyzed 37 episodes of PE seizures recorded in 30 patients during a single three-hour video/EEG recording. The PE seizures occurred spontaneously or were induced by sequential activation procedures. The historical information together with behavioral observations show that the PE seizures mimicked primary generalized seizures in 15 episodes, elementary partial seizures with secondary generalization in 21 episodes, and complex partial seizures in a single episode. Our data underscore the usefulness of the video/EEG recording method and suggest activation techniques which, combined with detailed historical information, aid in establishing the diagnosis of PE seizures.