Intraoperative ultrasonography was performed during 19 brain and two spinal cord operations. Intraoperative ultrasonography was requested for various reasons, localization of the lesion being the most frequent request, which was successfully accomplished in 18 out of 21 cases. Other minor reasons for intraoperative ultrasonography were differentiation of solid component from cystic portion, detection of mural nodule or scolex, depth measurement for punctrue, evaluation of residual lesion, which were almost all successful.