Many neuroimaging studies have implicated the orbital frontal cortex (OFC) in the pathophysiology of obsessive-compulsive disorder. In recent years there have been significant advances in elucidating the anatomical characteristics of the OFC in nonhuman primates. The authors review literature on the cytoarchitecture and afferent and efferent connections of the OFC, giving particular attention to the OFC's relationship to limbic and paralimbic regions, the mediodorsal thalamus, the basal ganglia, and sensory association cortices. These cytoarchitectural divisions and connections are discussed in terms of how they may influence thinking about the OFC's contribution to obsessive-compulsive disorder.