OBJECTIVE: The superior temporal gyrus, a heteromodal auditory and language association cortex, has been found to be smaller in patients with schizophrenia than in normal subjects. However, genetic and/or neurodevelopmental underpinnings of superior temporal gyrus alterations are unknown. Nonpsychotic children with greater genetic risk for schizophrenia exhibit language deficits. The authors studied the superior temporal gyrus in nonpsychotic children at risk for schizophrenia. METHOD: Magnetic resonance imaging was used to measure the right and left superior temporal gyrus of 29 young nonpsychotic subjects who had a parent with schizophrenia and 27 age- and sex-matched comparison subjects who had no family psychiatric history. RESULTS: After controlling for age and intracranial volume, the authors found that the volumes of the right and left superior temporal gyrus of the subjects at risk for schizophrenia were significantly smaller than those of the comparison subjects. Comparison subjects, but not at-risk subjects, showed an inverse correlation between age and left superior temporal gyrus volume. CONCLUSIONS: These findings provide new evidence that superior temporal gyrus abnormalities may result from genetically mediated developmental deviance reflecting greater susceptibility to schizophrenia. Further studies and follow-up will lead to greater understanding of the role of the superior temporal gyrus in the premorbid vulnerability to schizophrenia.