The value and main task of computerized tomography in the diagnosis of benign and malignant processes in the middle and upper facial skeleton lies in its accurate demonstration of the extent of the disease; this is important in relation to the planning of treatment, prognosis and to other complementary procedures. CT is a new and potent method for the TNM classification of tumours of the nose, paransal sinuses and nasal pharynx. The ability of the CT to demonstrate deeply situated structures in the face, without disturbing overlying shadows, makes precise staging of deep tumours possible, eg. stages T2-T4. The consequences in terms of pre-treatment TNM classification are discussed. In cases of fronto-basal fractures, the CT will show particularly trauma to the orbital contents, intracranial displacement of bone fragments and cerebral trauma with or without bleeding. Suspicion of orbital involvement by benign or malignant disease is a definite indication for a CT examination. As regards the middle and upper facial skeleton, computer tomography provides information of a morphological and quantitative nature and aids in the localisation of lesions. It should be properly integrated into the conventional clinical, endoscopic and tomographic methods employed in the diagnosis of lesions of the facial skeleton.