48 patients with pathologically confirmed primary osseous malignant lesions were examined by computed tomography (CT). In each case, the CT findings were compared with those from the standart radiographs, tomograms, angiography as well as the clinical findings in regard to the tumor detection, diagnosis and extent. Even though CT demonstrated all lesions, 87% were seen on plain radiographs with 13% of tumors identified solely by CT. In 75% of cases gave a better indication of tumor location, extent and relationship than did any of the other methods.