&NA;An intraoperative technique for deep brain biopsy is described. It features the use of an integrated surgical support system for the instruments and a rod that provides external topographical maintenance of the coordinates established ultrasonographically. A cystoscope, when supported mechanically by this system, permits multiple entries of the biopsy forceps to the lesion without further disturbance of the brain, as well as irrigation, coagulation, and visualization, if desired. When used in conjunction with real time intraoperative ultrasonography, the surgeon may view the entire procedure and be certain that the biopsy sample has been obtained from the lesion, major deep blood vessels have been avoided, and the biopsy site is stable after the procedure. The advantages of this technique include simplicity, low cost, accuracy, stability, and availability to every neurosurgeon in every hospital. (Neurosurgery19:49‐58, 1986)