Long-term monitoring of epileptic patients who are candidates for surgical therapy has developed at the Montreal Neurological Institute and Hospital over the last 15 years. Given the large number of patients being investigated, we had to develop procedures which were not labor-intensive. Our monitoring sessions require only the regular supervision of nursing staff. This allows monitoring to take place 7 days a week and 24 h a day on 2 or 3 patients, with minimal personnel requirement. The work of the EEGer is greatly simplified by the fact that the EEG tracing is reduced to the 'interesting' sections only. This was originally possible because of the concept developed by Ives et al. (1976) of delaying the EEG so that activity prior to perceptible clinical signs were always retained. The automatic detection of interictal spikes and seizures in the EEG complemented very effectively this original method of seizure recording. Video recording plays a critical role in the evaluation of seizure disorders. In order to have the maximum quality of EEG and behavior, we record them on their most appropriate medium, paper and video tape respectively; the two are synchronized by a common clock. EEGs are also recorded on a computer tape or disk and can be further analyzed for clinical and research purposes.