Thirty-six chronic schizophrenics and 24 controls, all males, were evaluated by computed tomography (CT) scans. The lateral, third and fourth ventricles, the Sylvian fissure and the largest sulcus from each lobe were measured. In the schizophrenic patients there was a significant increase in third ventricle, ventricular brain ratio (VBR) and cortical measures. The possible implications of these findings in the aetiopathology of schizophrenia are discussed.