Transcranial perfusion monitoring provides early warning of impending brain ischemia and may be used to guide management of cerebral perfusion and oxygenation. The monitoring options include measurement of intracranial and cerebral perfusion pressures, assessment of cerebral blood flow, and assessment of the adequacy of perfusion by measurement of cerebral oxygenation and brain tissue biochemistry. Some monitoring techniques are well established, whereas others are relatively new to the clinical arena and their indications are still being evaluated. Currently available monitoring techniques are reviewed and their appropriateness and application to the perioperative period is discussed.