We present a recordings of 37-year-old woman with simultaneous ictal scalp and subdural electrodes. The ictal rhythmon subdural electrocorticography (ECoG) started earlier (median 24.5 sec) and ended later (median 2.0 sec) compared toictal rhythm on scalp EEG. Eight ictal ECoG recordings were well localized to left temporal area, whereas ictal scalp EEGrecordings were not. Our case shows the obvious timing relations between two recordings, and different electrophysiologicinformation about localization of ictal onset zone.