Clinical, historical, neuropsychological, and biological correlates of lateral ventricular enlargement on computed tomography (CT scan) were explored in a sample of DSM-III schizophrenics. Patients with enlarged ventricles, as compared with those whose ventricles were normal, presented a longer duration of illness and mean duration of hospitalization, and higher scores on the subscales alogia, affective flattening, and attentional impairment of the Scale for the Assessment of Negative Symptoms (SANS), on the scales self-care, participation in household activities, work performance, and behavior in crises and emergencies of the Disability Assessment Schedule, on the scales rhythm, writing, reading, arithmetic, and left hemisphere of the Luria-Nebraska Neuropsychological Battery, and on the subtests digit span, digit symbol and block design of the Wechsler Adult Intelligence Scale. Furthermore, on the computerized electroencephalogram, beta relative activity was significantly higher in patients with normal ventricles on the right frontal, left frontal, and right central leads. On stepwise discriminant function analysis, the patient groups with enlarged and normal ventricles could be separated statistically, and duration of illness and summary score on the SANS were found to be the best discriminators.