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Obsessive-compulsive disorder is manifested by a group of symptoms including intrusive thoughts, rituals, mental obsessions and compulsions which creates great distress for the individual. Traumatic brain injurie known as one of the rare reasons of obsessive-compulsive disorder. This report is about 3 patients that suffer from obsessive-compulsive disorder after a traumatic brain injury and loss of consciousness. All 3 patients had no sign of obsessive-compulsive disorder before the trauma. Information on these reports, examine the relationship between obsessive-compulsive disorder and traumatic brain injury. Findings from the neuroimaging methods for these patients have been reported. In this study, all the reported cases that had sever traumatic brain injuries were assessed by neuroimaging methods and brain injuries were obsereved in the right temporal in first case, in the right temporal and both frontal sides in second case, in the splenium corpus callosum and the right brain tegmentums and diffused axonal injury and extra-axial hematoma in the left temporal lobein the thirtd patient. Based on the findings of this study obsessive-compulsive disorder can rarely be developed after a traumatic brain injury and by assessing the neuroimaging findings, we can conclude that there is a relationship between the brain injuries and the symptoms of obsessive-compulsive.