Interhemispheric pressure gradients may occur following severe head trauma in patients even in the absence of intracranial space occupying lesions. A higher ICP of the contralateral hemisphere may escape routine unilateral ICP monitoring. Clinical signs and CT scans do not seem to predict reliably a lateralized ICP. According to our data with a limited number of patients, interhemispheric pressure gradients seem to occur in the initial posttraumatic phase in some patients, and they seem to resolve following adequate ICP treatment after several hours. Therefore, simultaneous bilateral ICP measurement may be warranted in the initial posttraumatic phase.