WE PRESENT THE first use of intraoperative thermographical imaging for the surgical resection of a cerebral arteriovenous malformation. For obtaining intraoperative regional and functional thermographical images, a real-time mode infrared camera was installed to an operating microscope with an exclusively developed attachment device. Changes of the surface temperature of the cortical draining vein and the surrounding cortical surface were observed intraoperatively before and after the occlusion of the main feeder. Intraoperative functional thermography with cold physiological saline solution demonstrated a change in the heat clearance of the draining vein after complete obliteration of the feeder.