Objective. Cerebral herniation resulting from postischemic brain edema is the most common cause of death in patients with large cerebral infarctions. Early monitoring of intracranial pressure and application of necessary treatment procedures may have life-saving value. In this study, the data obtained by transcranial Doppler sonography were compared with clinical examination and the neuroradiologic findings. Methods. Eighteen patients with first-ever strokes and large middle cerebral artery infarction who were admitted within the first 12 hours after stroke onset were included. Clinical findings were evaluated according to the daily Glasgow Coma Scale and Rankin disability scores on the 10th day. Initial cerebral computed tomography was performed at admission to the hospital. Midline shift and ventricular displacement were evaluated on the third day. Follow-up tomographic scans of some patients were per-formed on subsequent days if necessary. Systolic, diastolic, and mean blood flow velocities and pulsatility indices of all patients were measured by transcranial Doppler sonography daily for 10 days. Results. The pulsatility indices were higher on the third hospital day than on the first day. The increases in the pulsatility indices were correlated with the midline shift measured on the third day. The prognoses of the patients whose maximal pulsatility indices during the first 10 days were higher than 1.5 were poorer than those of the patients whose maximal pulsatility indices were lower than 1.5. Conclusions. Transcranial Doppler sonography enables noninvasive monitoring of raised intracranial pressure in patients with large infarctions. It also provides information for detecting cerebral herniation and deciding on the medical or surgical therapy.