A comprehensive assessment of computed tomography (CT) with respect to clinical, historical and neuropsychological variables has been carried out in a sample of DSM III schizophrenics fairly heterogeneous with respect to duration and severity of illness and in a normal control group matched for sex, age and educational level. The mean value of ventricular brain ratio (VBR) was significantly higher in schizophrenics than controls. Seven patients (21.2%) who had VBRs exceeding 2 SD of the control mean showed a significantly longer duration of illness than the other schizophrenics with significantly higher scores on the subscales alogia, effective flattening and attentional impairment of SANS, on the scales self-care and behaviour in crises and emergencies of DAS, on the scales rhythm, tactile, visual, reading, arithmetic, memory and left hemisphere of LNNB, and on the subtests arithmetic, digit span, digit symbol and block design of WAIS. These results confirm earlier reports of an enlargement of lateral cerebral ventricles in a subset of schizophrenics, and its association with a higher degree of cognitive and neuropsychological impairment, social maladjustment and defectual symptomatology. Moreover, they suggest that the neuropathological process likely to underlie the increase of cerebral ventricular size progresses during the course of the illness rather than predating its onset.