A methodology was developed for dividing prefrontal cortical gray matter into insular, orbital, inferior, middle, superior, cingulate, and frontal pole regions using anatomical criteria. This methodology was developed as a follow-up to one that measured whole prefrontal gray and white matter volumes in schizophrenic and control subjects. This study showed no overall volume differences in prefrontal cortex between schizophrenic and control subjects. The parcellation of prefrontal cortex was done to increase the probability of detecting abnormalities that were circumscribed to a particular portion of the region. A 1.5 Tesla magnet was used to acquire contiguous 1.5-mm coronal slices of the entire brain. Volumes were then measured in a group of right-handed male (n = 15) subjects. Gray matter was parcellated using criteria that were mainly based on gross anatomy, as visualized in 3-dimensional renderings of the brain. Reliability of the parcellation scheme was very high (r(i) = 0.80 and above). This methodology should be useful in the study of cortical pathology in a number of neurological disorders, including schizophrenia.