There are many reports of clinical and biological gender differences in schizophrenia. Gender differences in structural brain abnormalities in schizophrenia have been reported on both computed tomographic (CT) and magnetic resonance imaging (MRI) scans. We present here a new MRI study of cerebral structures in schizophrenia. On the basis of previous findings, we hypothesized that schizophrenic males are more likely than females to show smaller brains and larger ventricles compared to their control counterparts. Our results indicated that the opposite was true: schizophrenic females, but not schizophrenic males, had smaller craniums and brains and larger lateral and third ventricles on MRI scans. The possible significance and implications of these data are discussed.