Two previously reported neuroimaging studies from the authors' laboratory demonstrated larger lateral ventricles in schizophrenic patients than in normal control subjects. This diagnostic effect was accounted for almost entirely by the male subjects. In this report the role of gender is further explored through reexamining these data sets and those of two earlier studies. Although Gender by Diagnosis effects were not demonstrated, in three of the four studies male schizophrenic subjects had significantly larger ventricles than their control counterparts; there were no differences among the female subjects. One study suggested the opposite effect, but this may be attributable to a non-representative control group.