It has been proposed that schizophrenia results partly from altered brain connectivity. Gene microarray analyses performed in gray matter have indicated that several myelin-related genes normally expressed in oligodendrocytes have decreased expression levels in schizophrenia. These data suggest that oligodendrocytes may be involved in the deWcits of schizophrenia and may be decreased in number in the case of disease. The anterior cingulate cortex in particular has been demonstrated to be aVected in schizophrenia, with studies reporting altered neuronal arrangement, decreased anisotropy in diVusion tensor images, and hypometabolism. We used a stereologic nearest-neighbor estimator of spatial distribution to investigate oligodendrocytes in the anterior cingulum bundle using postmortem tissue from 13 chronic schizophrenics and 13 age-matched controls. Using a spatial point pattern analysis, we measured the degree of oligodendrocyte clustering by comparing the probability of Wnding a nearest-neighbor at a given distance in schizophrenics and controls. At the same time, we also estimated the number and density of oligodendrocytes in the region of interest. In the present study, we found no signiWcant diVerences in the oligodendrocyte distribution or density in the cingulum bundle between the two groups, in contrast to earlier data from the prefrontal subcortical white matter. These results suggest that a subtler oligodendrocyte or myelin anomaly may underlie the structural deWcits observed by brain imaging in the cingulum bundle in schizophrenia.