Among 441 CT scans of 303 patients with a malignant tumor of the head or neck 138 scans of 83 patients were performed for evaluation of recurrent tumor. In diagnosing nodal recurrence computed tomography (CT) had a sensitivity of 92% (52 out of 56) and a specificity of 96% (55 out of 57). In diagnosing recurrence at the primary site sensitivity of 72% (56 out of 77) and specificity of 60% (30 out of 50) was lower and clearly inferior to physical examination with 92 and 88% respectively. CT was very useful in delineating advanced recurrencies, especially in regions that were not readily accessible by physical examination or were indurated by flat scarring. In addition to the complete staging of nodal involvement this makes CT the radiologic method of choice in follow-up of patients with malignant tumors of the head and neck. A post-therapeutic baseline scan obtained 6-8 weeks after surgery resp. radiotherapy is expected to further improve results, especially in differentiating scar from recurrent tumor.