This article presents a neuropsychological perspective on obsessive compulsive disorder (OCD) and describes some of the cognitive strengths and weaknesses that characterize the disorder. Neuroanatomic findings and theories of the neurologic basis of OCD are reviewed as are studies that use neuropsychological assessments. Findings of frontal lobe and/or basal ganglia dysfunction as well as memory deficits are emphasized. This information is then discussed in the context of cognitive-behavioral and information processing perspectives that emphasize normal patterns in anxiety and worry. The goal is to provide an integrated conceptual model of OCD, identifying the normal and abnormal information processing patterns that characterize the disorder.