We experienced a patient with acute thrombosis of the unilateral internal carotid artery. We monitored the brain tissue temperature and intracranial pressure not only in both hemispheres simultaneously but also continuously throughout the process of brain death. The patient was a 73-year-old male who presented to our emergency room with right hemiparesis and aphasia. On admission to our department, no specific pathological findings were identified by brain CT. However a following investigation with left carotid arteriogram demonstrated a complete occlusion of the left internal carotid artery. Probes to monitor intraparenchymal temperature (Tip) and intracranial pressure(ICP) were inserted surgically into the bilateral hemispheres, and these two parameters were monitored continuously until the patient's death. Initially, Tip in the infarcted hemisphere was lower than that in the intact hemisphere, and the left hemisphere's ICP was significantly higher than that of the right one. When the ICP in the left hemisphere exceeded 40 mmHg, bilateral ICPs became equal. Brain herniation was confirmed when the ICP became progressively elevated thereafter. Subsequently the bilateral Tips became equal and lower than the bladder temperature following the brain herniation. In this case, we successfully monitored two parameters while the patient was in the process of brain death; i.e., brain ischemia, complete loss of brain circulation and subsequent decrease in the brain tissue temperature.