A case of interhemispheric subdural hematoma (ISH) following closed head injury is reported. Our patient had seizures and mental status changes. Cranial computed tomography (CT) demonstrated areas of increased density along the right side of the falx cerebri and over the right leaf of the tentorium cerebelli. Conservative treatment was chosen and the patient recovered. Ten other patients with ISH were compared with ours. Head injury is the leading cause of ISH. Most patients display confusion, lethargy, or a "falx syndrome," with a delayed interval of prominent neurological deficits from the time of injury until presentation. Although patients with ISH can be successfully treated by medical management, surgical intervention may be required.