The purpose of this study was to test the hypothesis that abnormalities in the parvalbumin-containing subclass of local circuit neurons contribute to altered γ-aminobutyric acid (GABA) neurotransmission in the prefrontal cortex of schizophrenic subjects. Profile counts and somal size measures were made of parvalbumin-immunoreactive neurons in areas 9, 46, and 17 from 15 matched pairs of schizophrenic and normal comparison subjects. No differences in relative density, laminar distribution, or somal size of labeled neurons were found in any region. These findings suggest that altered GABA neurotransmission in schizophrenia is due to either abnormalities in other subpopulations of prefrontal cortical GABA neurons or abnormalities in the parvalbumin-containing subclass that could not be detected in the present study.