Brain maps were recorded on a patient with a multiple personality disorder (10 alternate personalities). Maps were recorded with eyes open and eyes closed during 2 different sessions, 2 months apart. Maps from each alternate personality were compared to those of the basic personality "S", some maps were similar and some were different, especially with eyes open. Findings that were replicated in the second session showed differences from 4 personalities, especially in theta and beta 2 frequencies on the left temporal and right posterior regions. A rank ordering of the differences in the brain maps of the alternate personalities from S were similar to the rank ordering of the differences in personality characteristics, as judged by the psychiatrist dealing with this patient. Maps from S acting like some of her personalities or from a professional actress portraying the different personalities did not reveal significant differences. Some of these findings are consistent with those in the literature, and the importance of detecting artifact in the raw EEG recording is emphasized.