Brains from patients with therapy-refractory schizophrenia were examined with respect to pyramidal cell disarray in the hippocampus, a finding reported in some studies, but not confirmed in others. A significantly higher number of disarrayed cells was seen in the brains of the schizophrenic patients in all subfields of the Cornu Ammonis (CA) investigated. Compared with controls the schizophrenic patients also had significantly fewer pyramidal cells in the observed areas of CA1-CA3, but not in CA4. There were no signs of gliosis. Finally, there was a significant negative correlation between the number of disarrayed cells and the total number of pyramidal cells in CA1-3 in the group of probands and controls taken together, a finding interpreted as lending support to the idea of a prenatal migratory disturbance in the pathogenesis of schizophrenic syndromes.