Four patients with head and neck tumors were observed by serial computed tomography (CT) during treatment. Osseous regeneration was demonstrated at sites of initial osteolytic destruction in two patients who responded to therapy. This regeneration was observed at 4 and 7 months, respectively, after the start of therapy. No such regeneration could be seen in the other two patients who did not respond to treatment. CT may be useful not only in demonstrating initial osseous invasion, but also in monitoring treatment response.