Image-guided surgery (IGS) is extremely useful for anatomic location in at-risk sinus surgery: extensive inflammatory disease, sinus cavity revision, and frontal sinus, posterior ethmoid, sphenoid or nasosinal tumor surgery. There are two systems on the market, based on electromagnetic and infrared detection, respectively; optimal functioning depends on calibration. IGS is only a location aid, complementary to and not a substitute for endoscopy. It enables the experienced endonasal surgeon to check the endoscopic location at any time, and provides appreciable “psychological” comfort in what are difficult and sometimes stressful operations, the limits of which are being forever pushed back.