Ten psychiatric patients with a DMS-III-R diagnosis of schizophrenia and persistent auditory hallucinations of at least 12 months' duration entered the study, and nine completed it. Subjects used portable audiocassette players with headphones to listen to two music audiotapes that they had selected, one for relaxing and the other for a stimulating/arousing effect. It was hypothesized that the relaxing music would reduce the frequency of auditory hallucinations more than the stimulating music. Subjects rated the effects of the music on nine scales for seven consecutive mornings. Analysed individually, six subjects reported significant response changes to the music, but the response pattern was heterogeneous, and the results of group analysis did not confirm the experimental hypotheses. Generally, the relaxing tape had more beneficial effects than the stimulating/arousing tape. Five subjects reported overall benefits from the experimental procedure, and in all five the content of their hallucinations was innocuous. One subject was adversely affected by the audiotapes, and three failed to respond; these subjects tended to have unpleasant or frightening hallucinations. It was concluded that headphone music was of some value as a non-pharmacological treatment for schizophrenic patients with persisting auditory hallucinations that were innocuous in content. Overall, the findings justify further research in the area.