In vivo morphological studies of the brain in schizophrenic patients, using computer tomography and magnetic resonance imaging, have provided information suggesting that schizophrenia is a brain disease. The most consistent findings of these studies are enlarged ventricles and volume reductions in the medial and lateral temporal lobes. Volume reductions of temporal cortex areas have been associated with the severity of positive symptoms such as delusions and hallucinations. Some of the morfological brain abnormalities may already be present before the onset of schizophrenia, and therefore may be directly related to the pathophysiology of the disease. In this article the relationship between in-vivo morphological findings and clinical variables, such as symptomatology, duration of illness and treatment response, will be discussed.