Low alpha frequency (less than 10.2 Hz) occurred more frequently in medication-free schizophrenic patients than in normal control subjects, as determined by quantitative EEG analysis. Furthermore, those patients with low alpha frequency had significantly larger lateral ventricles, as measured by CT scan, than did other schizophrenic patients (mean +/- SD ventricle-brain ratios = 9.8 +/- 1.9 versus 5.0 +/- 2.4; p less than 0.01). This finding suggests the existence of a relationship between cerebral structural pathology and the alpha rhythm that may be based on involvement of alpha-generating structures which border the cerebral ventricles. Future EEG studies of schizophrenia may resolve these questions in the context of other brain findings.