Intraoperative ultrasonography with real time sonographic imaging equipment is widely used and, in the neurosurgical operating room, has been really successful, initially in the brain and subsequently in the spinal cord as well. Its main applications i.e. accurate needle biopsies, localization of intracerebral masses, placement of ventricular and cyst shunts, can diminish the amount of potential damage to normal brain tissue. Moreover results of tumor resection may be intraoperatively confirmed and the end results are more accurate. No intraoperative complications and no postoperative infections result from use of ultrasound in the operating room. No evidence is given that the small amount of mechanical vibration emitted by the transducer damages the brain or the spinal cord. Surgical procedures, as a result, are faster, safer and better planned by virtue of informations obtained by ultrasonographic intraoperative examination, instead of simple preoperative imaging procedures.