The brains of 232 patients with a case-note diagnosis of schizophrenia or affective disorder who died in one mental hospital over a period of 22 years were weighed, and were assessed in a coronal section at the level of the interventricular foramina. From this sample were eliminated the brains of patients whose illnesses did not meet the Washington University criteria for a diagnosis of definite schizophrenia or primary affective disorder and those brains that showed significant histopathologic evidence of Alzheimer's-type change or cerebrovascular disease. This left a sample of 41 patients with schizophrenia and 29 patients with affective disorder. With age, sex, and year of birth controlled for, the brains of the patients with schizophrenia were 6% lighter, had lateral ventricles that were larger in the anterior (by 19%), and particularly in the temporal, (by 97%) horn cross section, and had significantly thinner parahippocampal cortices (by 11%). The findings provide postmortem confirmation of reports of ventricular enlargement in radiological studies and suggest that such enlargement is associated with tissue loss in the temporal lobe. The changes in schizophrenia were of a lesser degree than those seen in a sample of brains of patients with Alzheimer's-type dementia and Huntington's chorea.