A retrospective review of 302 previously untreated patients with primary supraglottic carcinoma was undertaken to ascertain the efficacy of postoperative radiotherapy. The 302 patients underwent a total of 383 functional neck dissections and 45 classic radical neck dissections. Pathological examination revealed nodal involvement in 117 patients (39%). In the histologically N0 group, the incidence of contralateral neck recurrence when a unilateral neck dissection and postoperative radiotherapy were carried out was 8%, rising 21% when no postoperative radiation was given. There was no difference in the ipsilateral recurrence rate in the N0 group, radiated patients (3%) and nonradiated patients (2%). Similar figures were found in the N1 group. Bilateral functional neck dissection in histologically N0, N1, and N2 necks had similar recurrence rates with or without radiotherapy. Distant metastasis appeared in 10% of N0 patients and in 35% of N3 patients. Patients who received postoperative radiotherapy showed a significantly higher rate of distant metastasis (21%) than patients who did not (8%). The number of involved lymph nodes had no relevance both in neck recurrence and distant metastasis.