Kernohan-Woltman notch phenomenon is a paradoxical neurological manifestation which involves a motor deficit on the same side as the primary brain injury. It is produced mainly by acute or chronic subdural hematomas, and less frequently by post-traumatic epidural ones. It should be taken into consideration in cases of ipsilateral motor deficit, as it may lead to surgical procedures being performed on the incorrect side. We report the case of a 40 year old man who sustained a major head injury which was followed by a decreased level of consciousness and anisocoria. Computed tomography of the brain revealed a frontal and parietal epidural hematoma with right midline shift and uncal herniation. Craniotomy and drainage of the hematoma was performed, and on the sixth day after surgery it was observed that the patient had a brachio-crural right hemiparesis. Magnetic resonance imaging showed an ischemic area on the left capsule and cerebral peduncle consistent with the diagnosis of Kernohan-Woltman notch phenomenon.