The extension of paranasal sinus malignant neoplasms into the orbit presents one of the arguments for carrying out orbital exenteration. One method of assessing the extension is computed tomography (CT), but its reliability is still questionable. Therefore, the preoperative CT images were compared with the pathoanatomic features of the surgical specimens in 15 patients who underwent orbital exenteration as part of a procedure for paranasal sinus malignant neoplasm. Ophthalmic symptoms were present in eight patients and in each instance the CT images documented the extension of the tumor accurately. In only four of seven patients without ophthalmic symptoms did CT scanning appear to match the factual situation. Apparently CT scanning is not always reliable in patients without ophthalmic symptoms.