Ultrasound imaging has become a common method for intraoperative evaluation of the central nervous system. Real-time monitoring aids in guidance for aspiration of fluid collections and placement of catheters as well as the localization and evaluation of masses, and confirmation of their complete removal. Color Doppler is useful in the evaluation of blood flow in arteriovenous malformations, aneurysms, and neoplasms. Consultation among the ultrasound staff, neuroradiologists, and neurosurgeons before the operative procedure maximizes the usefulness of ultrasound, thus aiding in the success of surgery.