Regional cerebral blood flow was measured using a 133Xe inhalation technique in 16 schizophrenic patients and 20 healthy volunteers. The bilateral frontal blood flows in the patient groups were significantly lower than in the control group. In addition, the patient group having auditory hallucination showed a significantly increased blood flow predominantly in the left temporal region. On the other hand, the patient group without auditory hallucination showed a slightly increased flow in the right temporal region. These findings indicate that there are a hypofrontal activity and also a hypertemporoparietal activity in schizophrenics.